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OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

LOS  ANGELES 


^OTT^ 


ATLAS  AND  EPITOME 


OPHTHALMOSCOPY 


Ophthalmoscopic  Diagnosis 


BY 

PROF.   DR.   O.   HAAB 

of  Zurich 


SECOND  AMERICAN  EDITION    FROM  THE    FIFTH  REVISED 
AND  ENLARGED  GERMAN  EDITION 


EDITED   BY 


G.   E.   DE  SCHWEINITZ,  A.M.,  M.D. 

Professor  of  Ophthalmology  in  the  University  of  Pennsylvania  and   Ophthalmic 
Surgeon  to  the  University  Hospital  ;    Consulting  Ophthalmic  Surgeon  to 
the  Philadelphia  Polyclinic  ;    Ophthalmic  Surgeon   to  the  Phila- 
delphia General  Hospital  ;   Ophthalmologist  to  the  Ortho- 
pedic Hospital  and  Infirmary  for  Nervous  Diseases 


With  t52  Colored  Liihographic  Iltusirations 


PHILADELPHIA  AND  LONDON 

W.  B.  SAUNDERS  COMPANY 

19  10 


Set  up,  Electrotyped,  Printed,  and  Copyrighted  May,  1901.     Reprinted 

September,  1904,  March,  1905,  and  March,  1906.     Revised, 

Reprinted,  and  Recopyrighted  March,   1909 


Copyright,  1909,  by  W.  B.  SAUNDERS  COMPANY 


Raprinted  March,  1910 


PRINTED    IN    ANfcRICA 


PRESS    OF 
SAUNDERS    COMPANY 
PHILADELPHIA 


vouP 
EDITOR'S  PREFACE  TO  SECOND  EDITION 


The  continued  favor  which  has  been  accorded  to  Pro- 
fessor Haab's  Ophthalmoscopy  and  Ophthalmic  Diagnosis 
has  made  necessary  a  new  edition,  in  which  the  subject- 
matter  has  been  brought  up  to  date  and  a  few  new 
chromo-lithographs  have  been  added,  several  from  Pro- 
fessor Haab^s  collection  and  one  from  the  collection  of 
the  editor.  It  can  scarcely  be  doubted  that  this  book 
will  prove  in  the  future,  as  it  has  in  the  past,  of  the 
greatest  use  to  those  w'ho  desire  to  study  and  teach 
Ophthalmology. 


EDITOR'S    PREFACE    TO    FIRST    EDITION 


The  great  value  of  Professor  Haab's  Atlas  of  Ophthal- 
moscopy and  Ophthalmoscopic  Diagnosis  has  been  fully 
established,  and  entirely  justifies  an  English  translation 
of  his  latest  edition.  Not  only  is  the  student  made  ac- 
quainted with  carefully  prepared  ophthalmoscopic  draw- 
ings, done  into  well-executed  lithographs,  of  the  most 
important  fundus-changes,  but  in  many  instances  plates 
of  the  microscopic  lesions  are  added.  The  whole  fur- 
nishes a  manual  of  the  greatest  possible  service,  not  only 
to  the  beginner  in  ophthalmic  work,  but  to  one  who  has 
already  far  advanced  and  desires  to  compare  the  observa- 

3 


4  PREFACE 

tions  of  his  own  service  with  those  of  the  rich  clinic 
from  which  Professor  Haab  has  gathered  his  phites.  A 
few  figures  have  been  added  by  the  editor — namely, 
those  showing  Angioid  Streaks  in  the  Retina,  and  the 
Ophthalmoscopic  Appearances  seen  in  Arteriosclerosis. 
As  in  the  Atlas  of  External  Diseases  of  the  Eye,  produced 
under  the  same  editorship,  occasional  comments  are  placed 
in  brackets.  It  is  sincerely  trusted  that  this  book  will 
prove  of  great  use  to  those  wdio  desire  to  study  and  teach 
Ophthalmology. 


PREFACE  TO  FIFTH  EDITION 


Although  this  atlas  was  already  very  much  greater 
than  the  first  edition,  it  was  nevertheless  possible,  thanks 
to  the  kindness  of  the  publisher,  to  enlarge  the  present 
fifth  edition  by  the  addition  of  two  illustrations  of  birth 
injuries  of  the  eye.  An  illustration  of  pigmentary  de- 
generation of  the  retina  which  was  not  quite  satisfactory 
was  replaced  by  a  better  one.  In  addition,  several  of  the 
earlier  illustrations  were  retouched  and  corrected  in 
various  ways.  Some  corrections  and  additions  have  also 
been  made  in  the  text,  and  it  is  hoped  that  this  edition, 
like  its  predecessors,  may  meet  with  the  approval  of  the 
profession. 

O.  Haab. 


PREFACE  TO  THE  SECOND  EDITION. 


The  kind  reception  accorded  to  this  volume  in  various 
countries  induced  me  to  make  a  number  of  additions  and 
corrections  before  the  book  went  through  the  second 
edition.  Besides  adding  to  the  text,  I  enriched  the 
illustrated  portion  of  the  work  by  a  number  of  anatomic 
figures  to  illustrate  the  differences  between  normal  and 
pathologic  appearances  of  the  eye-ground.  They  are 
intended  to  explain  the  things  seen  under  the  micro- 
scope and  their  topographic  relations,  thus  enriching  the 
student's  pathologic  knowledge  and  enabling  him  to  in- 
terpret more  accurately  the  clinical  pictures  presented 
by  the  various  diseases. 

A  few  of  the  original  ophthalmoscopic  pictures  have 
been  replaced  by  better  ones,  and  two  have  been  added 
that  are  entirely  new  (retinitis  circinata  and  true  staphy- 
loma in  myopia). 

For  the  preparation  of  the  anatomic  figures  I  am 
indebted  to  the  skill  of  our  academic  artist,  Mr.  L. 
Schroter. 

Although  the  pupillometer  (Fig.  80,  a)  does  not,  strictly 
speaking,  belong  to  the  subject  of  ophthalmoscopy,  I 
have,  nevertheless,  yielding  to  a  long-cherished  desire, 
incorporated  it  in  this  book — which  is,  above  all,  in- 
tended for  practical,  every-day  use — believing  that  many 

5 


6  PREFACE  TO  THE  SECOND  EDITION. 

practitioners  who  feel  the  necessity  of  determining  the 
size  of  the  pupil  more  accurately  than  is  possible  by 
mere  inspection  will  find  it  a  welcome  addition  to  their 
clinical  armamentarium. 

Finally,  I  wish  to  express  my  grateful  recognition  of 
the  great  care  and  effort  bestowed  on  the  preparation  of 
this  Atlas  by  the  publisher. 

O.  HAAB. 


CONTENTS. 


PAGE 

Introduction 13 

Description  of  the  Ophthalmoscope 18 

Examination  in  the  Erect  Image 23 

Measurement  of  the  Myopic  Eye      26 

Measurement  of  the  Hypermetropic  Eye 29 

Measurement  of  Astigmatism 34 

Size  of  the  Ophthalmoscopic  Field  of  Vision 38 

Examination  by  the  Indirect  Method 40 

Size  of  the  Visual  Field 42 

Enlargement  of  the  Image  in  the  Direct  and  in  the  Indi- 
rect Methods 43 

Measurement  of  Refraction  by  the  Indirect  Method    ...  45 
Determination  of  Irregularities  in  the  Surface  of  the  Eye- 
ground     45 

Examination  by  Transmitted  Light      47 

Shadow-test,  or  Skiascopy 53 

Choice  of  an  Ophthalmoscope 58 

Method  of  Conducting  an  Ophthalmoscopic  Examination  67 

Normal  Eye-Ground 74 

Pulsation  Phenomena 82 

INDEX 89 

7 


ILLUSTRATIONS 


FIG. 

1. 

2, 

a, 

b. 

3. 

4. 

5, 

a, 

b. 

6. 

7. 

8, 

a. 

8, 

b. 

9, 

a. 

9, 

h. 

10, 

a. 

10, 

b. 

11. 

12, 

a, 

b. 

13, 

0, 

b. 

13, 

A. 

14, 

a-c. 

15, 

a. 

15, 

b. 

16. 

17. 

18. 

19, 

a, 

b. 

20, 

a, 

b. 

.21, 

a. 

21, 

b. 

22. 

28, 

a, 

b. 

24, 

a. 

Normal  Eye-ground. 

Section  of  a  Normal  Papilla. 

Section  of  the  Retina,  Choroid,  and  Contiguous  Sclera  in  a 
Normal  Eye. 

Normal  Eye-ground  (Blonde). 

Normal  Eye-ground  (Dark). 

Medullated  Nerve-fibers  in  the  Retina. 

Congenital  Circumscribed  Defect  of  the  Choroid. 

Congenital  Circumscribed  Defect  of  the  Choroid  and  Mal- 
formation of  the  Optic  Nerve. 

Congenital  Defect  of  the  Pigment-epithelium  of  the  Retina. 

Congenital  Circumscribed  Defect  of  the  Retinal  Pigment 
and  the  Choroid. 

Congenital  Circumscribed  Defect  of  the  Choroid. 

Congenital  Circumscribed  Defect  of  the  Choroid. 

Congenital  Absence  of  Pigment. 

Congenital  Dislocation  of  the  Lens. 

Inflammation  of  the  Optic  Nerve. 

Inflammation  of  the  Optic  Nerve  in  Brain-tumor. 

Optic  Neuritis  (Choked  Disc)  and  Macular  Changes  in  Brain- 
tumor. 

Horizontal  Section  of  a  Normal  Macula  Lutea. 

Section  through  the  Papilla  in  Neuritis. 

Section  through  the  Papilla  in  Neuritis  and  Papillitis. 

Inflammation  of  the  Optic  Nerve  and  Retina  in  Syphilis. 

Intense  Inflammation  of  the  Optic  Nerve. 

Inflammation  and  Congestion  of  the  Optic  Nerve  in  Orbital 
Tumor. 

Atrophy  of  the  Optic  Nerve. 

Gray  Atrophy  of  the  Optic  Nerve. 

Section  through  Entrance  of  the  Optic  Nerve  in  Partial 
Atrophy. 

Section  through  the  Disk  in  Total  Atrophy  of  the  Optic  Nerve. 

Atrophy  of  the  Optic  Nerve  from  Glaucoma. 

Glaucomatous  Excavation  of  the  Optic  Nerve. 

Section  through  the  Region  of  the  Angle  of  the  Antei-ior 
Chamber. 


10  ILLUSTRATIONS. 


Section  through  Same  Kegion,  showing  Obliteration  of  Angle. 

Section  through  the  Head  of  the  Optic  Nerve  in  Glaucoma. 

Retina  and  Optic  Nerve  in  Albuminuria. 

Section  through  the  Retina  in  Retinitis  Albuminurica. 

Varicose  Nerve-fibers. 

Retina  in  Retinitis  Albuminurica. 

Albuminuric  Changes  in  Retina  ai>d  Optic  Nerve. 

Albuminuric  Disease  of  the  Eye-ground. 

Albuminuric  Retinitis  of  Both  Eyes. 

Eye-ground  in  Diabetes. 

Eye-ground  in  Pernicious  Anemia. 

Obstruction  of  the  Central  Artery. 

Thrombosis  of  the  Superior  Temporal  Vein. 

Thrombosis  of  the  Central  Vein  of  the  Retina. 

Obstruction  of  the  Superior  Temporal  Artery  of  the  Retina. 

Recurring  Hemorrhages  in  the  Retina  and  Vitreous. 

Syphilitic  Disease  of  the  Retinal  Arteries. 

Syphilitic  Neuroretinitis  and  Disease  of  the  Retinal  Arteries. 

Angioid  Streaks  in  the  Retina. 

Changes  in  the  Eye-ground  in  Arteriosclerosis. 

Pigmentary  Degeneration  of  the  Retina. 

Eye-ground  in  Hereditary  Syphilis. 

Eye-ground  in  Congenital  Syphilis. 

Secondary   Pigmentation   of   the    Retina   in   Disseminated 

Choroiditis. 
Disease  of  the  Macula  Lutea  due  to  Myopia. 
Secondary  Pigmentation  of  the  Retina. 
Sagittal  Section  of  an  Eye  with  a  Total  or  Funnel-shaped 

Retinal  Detachment. 
d.  Pigmentary  Degeneration  of  the  Retina. 
Disease  of  the  Macula  Lutea  due  to  Old  Age. 
Disease  of  the  Macula  Lutea  (Traumatic). 
Perforation  of  the  Macula  Lutea  after  Contusion  of  Eyeball. 
Macula   Lutea  and   Surroundings  in  Disease  from  Orbital 

Tumor. 
Retina  in  Thrombosis  of  the  Vena  Centralis  RetinoB. 
Opacity  of  the  Retina. 

Disease  of  the  Macula  Lutea  due  to  Foreign  Body. 
Disease  of  the  Macula  Lutea  due  to  Pressure  and  Contusion. 
Injury  of  the  Retina  by  an  Iron  Splinter. 
Air-bubble  in  Vitreous. 
Old  Injury  of  the  Retina  by  an  Iron  Splinter. 


FIG. 

24, 

h. 

24, 

<^, 

d. 

25, 

a. 

b. 

26, 

a. 

26, 

f>, 

c. 

27. 

28, 

a. 

28, 

h. 

29, 

o, 

b. 

30, 

a. 

b. 

31. 

32. 

33, 

a. 

33. 

b 

34. 

35. 

36. 

37. 

37, 

a. 

>37, 

b. 

38, 

39 

40. 

41, 

42 

43. 

44, 

45 

46, 

a. 

46, 

b. 

46, 

c, 

d. 

47. 

48. 

49. 

50, 

a. 

50, 

b. 

c. 

51, 

52, 

63. 

54. 

55. 

56. 

57. 

ILLUSTRATIONS.  11 

FIG. 

58,  a.  Point  of  Impact  of  a  Foreign  Body  on  tlie  Eye-ground. 

58,  6.  Ketinal  Bands  due  to  Traumatism. 

58,  I,  a.  Changes  in  Eye-ground  Resulting  from  Severe  Forceps  Delivery. 

58.  I,  h.  Atrophy  of  the  Optic  Nerve  and  Retinal  Vessels ;  Macular 

Disease ;  Strand  of  Connective  Tissue  in  Vitreous. 

59.  Retinal  Detachment  in  the  Temporal  Portion  of  the  Eye- 

ground. 

60.  Retinal  Bands  and  Detachment  after  a  Punctured  Wound. 

61.  Retinal  Detachment  at  the  Inner  Upper  and  Lower  Portions. 

62.  Retinal  Detachment  with  Laceration. 

63.  Hemorrhagic  Retinitis  of  Pregnancy. 

64.  Retinitis  Circinata. 

65.  Eye-ground  in  Leukemia. 

66.  Glioma  of  the  Retina. 

67.  a.        Retina  in  Pernicious  Anemia. 

67,  6.         Small  Inflammatory  Focus  in  Disseminated  Choroiditis. 

68,  69.      Disseminated  Choroiditis. 

70.  Infiltrations  of  the  Choroid  in  Disseminated  Choroiditis. 

71.  Disseminated  Choroiditis  in  the  Early  Stage. 

72.  a.        Hyaline   Bodies    (Drusen)    in   the  Vitreous   Layer  of  the 

Choroid. 

72,  6.        Senile  Pigmentation  of  the  Retina. 

73,  a.        Recent  Disseminated  Inflammation   of  the  Choroid,  Over- 

lying Retina,  and  Optic  Nerve. 

73,  6.        Disseminated  Choroiditis. 

74.  Chronic  Disseminated  Choroiditis  and  Secondary  Pigmenta- 

tion of  the  Retina. 
Miliary  Tubercles  in  the  Choroid. 
Chronic  Tuberculosis  of  the  Choroid. 
Sarcoma  of  the  Choroid. 
Recent  Disseminated  Choroiditis. 

Changes  in  the  Choroid  due  to  Contusions  ;  Lacerations. 
Sclerosis  of  the  Choroidal  Vessels  ;  Disseminated  Choroiditis 

and  Secondary  Pigmentation  of  the  Retina. 
Hyaline  Bodies  (Drusen)  of  the  Vitreous  Layer. 
Miliary  Tubercle  of  the  Choroid. 
Large  Tubercular  Growth  in  the  Choroid. 
Choroidal  Sarcoma. 
Atrophy  of  Choroid  in  Myopia. 
True  Staphyloma. 
Posterior  Venae  Vorticosae. 
Pupillometer. 


OPHTHALMOSCOPY 


INTRODUCTION. 


Examination  of  the  eye-ground  by  means  of  the 
ophthalmoscope  is  of  the  highest  importance  for  the 
recognition  not  only  of  many  affections  of  the  eye  itself, 
but  also  of  a  great  number  of  diseases  chiefly  affecting 
organs  outside  of  the  eye,  as  the  brain,  the  kidneys, 
or  the  circulatory  system,  and  endangering  life  either  by 
disturbing  the  general  nutrition  or  by  setting  up  a  general 
infection.  The  wide  lymph-spaces  of  the  eye  and  the 
rich  network  of  vessels  in  the  retina  offer  a  favorable 
soil  for  the  development  of  many  pathogenic  germs  and 
toxic  substances  present  in  the  body.  This  is  especially 
noteworthy  in  syphilis,  both  in  the  hereditary  and  in 
the  acquired  variety,  although  the  effects  of  tubercular 
and  rheumatic  infection  of  the  organism  also  not  infre- 
quently manifest  themselves  in  the  eye. 

For  these  reasons  ophthalmoscopic  examination  of  the 
eye-ground  is  one  of  the  most  important  methods  of 
medical  examination.  Unfortunately,  it  is  also  one  of 
the  most  difficult.  This  is  partly  because  the  familiar- 
ity with  the  technic  of  the  ophthalmoscope  necessary  for 
obtaining  a  clear  image  of  the  eye-ground  requires  a 
certain  amount  of  training  and  practice,  and  partly 
because  the  correct  interpretation  of  the  ophthalmoscopic 
injage  is  often  a  very  difficult  matter.  An  astonishing 
variety  of  pictures  may  be  seen  in  the  interior  of  the  eye. 
The  image  of  the  eye-ground  varies  greatly  even  in  con- 
ditions of  health,  and  it  is  anything  but  easy  for  the 
beginner   in    the    art   of  ophthalmoscopy  to  determine, 

13 


14  OPHTHALMOSCOPY. 

in  many  instances,  whether  the  conditions  present  are 
normal  or  pathologic.  If,  for  instance,  he  should  de- 
scribe the  fundus  of  the  eye  as  "  abnormally  reddened, '^ 
an  expert  would  know  that  he  has  to  deal  with  a 
beginner. 

Still  more  difficult  is  the  interpretation  of  the  numer- 
ous deviations  from  the  normal  which  may  be  seen  in 
the  eye-ground.  It  is  comparatively  easy  for  one  who 
sees  only  the  coarser  variations,  because  he  fails  to  utilize 
the  instrument  to  its  fullest  extent,  or  because  the  in- 
strument itself  is  imperfect,  or,  possibly,  because  his  eye 
is  not  sufficiently  well-trained  or  is  defective,  or  his  ex- 
amination is  too  hasty.  Even  the  expert  often  finds  the 
greatest  difficulty  in  seeing  and  correctly  interpreting  the 
more  minute  pathologic  alterations  in  the  eye-ground. 
Practice  and  experience,  both  the  examiner's  own  and 
that  of  other  observers,  in  this,  as  in  many  other  cases, 
will  prove  to  be  the  best  guides.  The  latter  may  be 
either  described  in  words  or  illustrated  by  pictures  which 
more  or  less  faithfully  reproduce  pathologic  alterations. 

Mere  verbal  descriptions  are  even  more  unsatisfactory 
than  they  are  in  other  similarly  complicated  domains 
of  medicine,  especially  if  the  student  is  imperfectly 
acquainted  with  the  subject.  Even  topographical  draw- 
ings of  pathologic  alterations  in  the  eye  are  extremely 
complicated,  and  a  correct  description  of  the  coloring  is 
often  extremely  difficult  or  even  impossible.  Thus,  a  little 
more  white,  or  a  little  more  red  or  gray,  may  make  an 
important  difference  in  the  appearance  of  the  optic  nerve, 
and  may  be  enough  to  show  the  expert  that  he  has  to 
deal  with  a  serious  condition,  though  to  the  inexperienced 
eye  the  appearance  may  be  normal.  It  is  for  this  reason 
that  the  examination  of  the  eye-ground  by  means  of  the 
ophthalmoscope  offers  an  excellent  means  of  training  the 
eye  for  the  perception  of  the  finest  shades  of  color — a 
most  useful  faculty  for  enabling  one  to  recognize  many 
other  morbid  alterations  in  the  body.  Black  and  white 
pictures   of  the  eye-ground  have,  therefore,  very  little 


A 


INTRODUCTION.  15 

value.  They  may  reproduce  the  drawing  and  topog- 
raphy, but  as  they  fail  to  give  the  important  element  of 
color,  they  can  be  understood  and  utilized  only  by  one 
who  already  possesses  a  fair  knowledge  of  the  conditions 
portrayed.^ 

To  supplement  one's  own  observations  and  profit  by 
those  of  others,  one  must  use  carefully  colored  illustrations. 

Although  we  already  possess  a  great  number  of  illus- 
trations of  the  eye-ground,  both  in  the  usual  atlases  and 
in  other  works,  I  am  none  the  less  determined  to  publish 
this  epitome  and  atlas  of  ophthalmoscopy.  In  the  first 
place,  the  pictures  that  exist,  especially  those  that  are 
scattered  through  the  literature,  are  not  accessible  to 
everyone,  and  I  find  that  many  a  picture  which  would 
be  useful  to  the  student,  to  the  practising  physician,  or  to 
the  clinical  teacher  for  the  purpose  of  study  and  demon- 
stration, is  not  found  in  these  works.  Too  many  of  the 
pictures  reproduce  rare  conditions  which  even  a  man 
of  large  practice  might  not  see  more  than  once  or  twice 
in  his  experience.  Again,  many  pictures  of  immense 
practical  importance,  especially  such  as  illustrate  sub- 
varieties  and  different  stages  of  the  same  morbid  process, 
are  often  left  out.  Thus,  for  instance,  it  is  impossible 
to  explain  to  the  beginner  the  variations  of  the  retina 
and  optic  nerve  in  albuminuria  by  means  of  one  or  two 
pictures,  or  the  manifold  forms  of  chronic  choroiditis 
with  three  or  four  illustrations.  Accordingly,  I  have 
tried  to  avoid  showing  very  rare  conditions,  and  have 
instead  collected  as  many  pictures  of  practical  importance 
as  possible.  All  the  ophthalmoscopic  images  contained 
in  this  volume  were  drawn  from  life  by  myself  in  the 
course  of  my  practice,  and  the  original  ophthalmoscopic 
pictures  are  also  of  my  own  preparation.  In  doing  this 
work    the    sketch-book^    was    found    extremely    useful, 

^  It  is  very  mucli  to  be  regretted  that  the  illustrations  in  the  excellent 
work  by  Gowers,  Medical  Ophihahnoscopy,  are  not  all  colored. 

2  Sketch-book  for  Ophthnlmoscopic  Observations  of  the  Ei/e-ground,  second 
edition,  unbound.     Published  by  J.  F.  Lehman,  in  Munich,  1898. 


16  OPHTHALMOSCOPY. 

because  it  combines  rapid  execution  with  the  greatest 
possible  degree  of  accuracy  in  reproducing  the  various 
shades  of  color.  With  the  exception  of  three  (Figs.  10,  b, 
39,  and  45,  a),  all  the  original  pictures  in  this  book  have 
been  prepared  according  to  my  own  method,  and  I  am 
convinced  that  it  is  the  easiest,  and  what  is  more  impor- 
tant in  drawing  from  life,  the  quickest  method  of  obtain- 
ing a  picture  of  all  the  alterations  seen  in  the  eye-ground. 

To  become  an  expert  in  the  beautiful  art  of  ophthal- 
moscopy it  is  necessary  to  do  a  great  deal  of  drawing  from 
life.  I  have  become  more  and  more  convinced  of  this 
during  the  preparation  of  the  pictures  in  the  present 
volume.  The  eye-ground  would  be  studied  with  much 
more  care  if  the  student  were  to  draw  ^  what  he  sees,  and 
especially  if  he  were  also  to  reproduce  the  colors.  The 
benefit  derived  from  a  course  in  ophthalmoscopy  will  be 
very  much  greater  if  the  student  draws  what  he  sees.  I 
constantly  regret  that  our  medical  students  are,  as  a  rule, 
so  badly  instructed  in  the  art  of  drawing,  and  that  so  few 
of  them  can  be  expected  to  produce  a  fairly  decent  pict- 
ure ;  but  even  an  imperfect  picture  is  better  than  none 
at  all  for  beginners. 

It  is  particularly  desirable  for  the  student  and  prac- 
tising physician  to  have  his  ophthalmoscopic  pictures  in 
a  more  convenient  form  than  the  usual  atlases,  and  the 
idea  of  presenting  them  in  book  form  seems  to  me  an 
excellent  one. 

The  pictures  in  this  volume  are  represented  as  they 
appear  in  the  inverted  image ;  that  is  to  say,  with  mod- 
erate magnification,  although  I,  of  course,  also  used  the 
more  highly  magnified  image  obtained  by  the  direct 
method  in  preparing  the  sketches  which  are  taken  from 
life.  The  figures,  therefore,  present  a  moderately  en- 
larged image  of  the  eye-ground,  leaving  out  many  con- 

1  Slcetch-booTc,  p.  4  :  "  The  ophthalmoscopist  who  possesses  any  proficiency 
in  the  art  of  drawing  will  notice,  incidentally,  that  the  drawing  of  these 
sketches  sharpens  his  powers  of  observation  and  impresses  the  picture 
more  firmly  on  his  memory.  If  we  intend  to  draw  a  thing,  we  are  forced 
to  observe  it  much  more  accurately." 


INTRODUCTION.  17 

ditions  which  naturally  confuse  the  beginner  and  are 
unnecessary  for  the  expert,  such,  for  instance,  as  the 
reflexes  of  the  retina  and  vessels,  and  the  delicate,  irreg- 
ular mosaic  arrangement  of  the  pigmentation  of  the 
fundus,  etc.  These  details,  which  are  seen  chiefly  in  the 
upright  image,  are  very  troublesome  to  reproduce  in 
lithographic  plates,  especially  when  one  considers  that 
the  lithographic  reproduction  of  even  a  small  image  of 
the  eye-ground  presents  great  difficulties.  I  therefore 
directed  all  my  efforts  to  obtaining  in  every  instance  an 
absolutely  faithful  reproduction  of  whatever  is  typical 
or  pathologic.  The  pictures  have  been  so  colored  that 
when  seen  in  daylight  they  produ(5e  the  impression  re- 
ceived in  looking  at  the  eye-ground  with  artificial  light ; 
in  other  words,  the  whitish  parts  (optic  nerve,  etc.)  when 
seen  by  daylight  are  not  as  yellow  as  they  are  in  the 
original  sketches,  which  were  made  by  artificial  light. 
In  an  artificial  or  yellow  light  a  moderately  deep  yellow 
color  appears  white,  hence  pictures  prepared  by  artificial 
light  are  too  yellow  and  must  be  made  more  white  if  they 
are  to  produce  the  same  impression  by  daylight.  The 
pictures  in  Jager's  large  atlas  are  colored  in  such  a  way 
that  they  appear  correct  by  artificial  light;  but  if  they 
are  examined  by  daylight  the  unnaturally  yellow  color 
of  the  lighter  portions  becomes  a  disturbing  factor.  My 
pictures,  on  the  contrary,  are  a  little  too  white  by  artificial 
light,  but  to  judge  from  all  the  pictures  in  ordinary  use 
this  is  neither  a  serious  nor  a  disturbing  defect.  In  his 
smaller  atlas  Jager,  in  accordance  with  the  custom  which 
arose  later,  also  made  his  pictures  more  white ;  but,  it  is 
to  be  remembered  that  Jilger's  pictures  were  prepared 
with  Helmholtz's  ophthalmoscope,  so  that  in  many  of 
them  the  gray,  and  particularly  the  green,  shades  in  the 
optic  disk  are  unusually  prominent  (for  instance,  in  the 
picture  of  glaucoma).  In  my  pictures  the  coloring  is 
such  as  it  appears  with  the  stronger  ophthalmoscope, 
which,  for  reasons  to  be  given  later,  I  use  exclusively 
in  the  examination  of  the  eye-ground. 
2 


1 8  OPHTHALMOSCOPY. 


DESCRIPTION   OF  THE  OPHTHALMOSCOPE. 

Before  the  jjM'ention  of  the  ophthalmoscope  by  H.  v. 
Hehiiholtz,  in  1851,  our  knowledge  of  the  interior  of  the 
eye  in  the  living  subject  was  as  dark  as  the  pupil  itself. 
Until  the  invention  uf  our  beautiful  instrument  the  world 
had  no  conception  of  the  interior  of  the  eyeball  as  we 
now  see  it  with  the  ophthalmoscope  in  all  its  lucidity  and 
wealth  of  coloring.  Most  of  the  pathologic  alterations 
visible  by  means  of  the  ophthalmoscope  were  not  even 
properly  known  at  that  time. 

Why  is  it  that  w^e  cannot  without  the  aid  of  an  appro- 
priate instrument  penetrate  into  the  depths  of  the  eye? 
Why  is  it  that  the  interior  of  the  eye  and  the  pupil 
appear  black  except  in  a  man  or  animal  devoid  of  pig- 
ment (albino)? 

The  conditions  are  exactly  the  same  as  when  we  look 
into  a  camera  obscura — as,  for  instance,  a  photographic 
apparatus  open  and  ready  for  the  reception  of  an  image — 
although  we  know  that  on  the  sensitive  white  plate  at  the 
back  of  the  instrument  there  is  an  accurate  colored  image 
of  the  objects  in  front  of  it,  w^e  cannot  see  a  trace  either 
of  the  white  plate  or  of  the  picture.  To  us  the  interior 
of  the  camera  and  the  opening  through  which  the  rays  of 
light  enter  appear  black,  and  all  that  we  see  in  the  lens 
occupying  this  opening  is  a  minute  image  of  ourselves, 
such  as  may  be  seen  in  the  cornea  of  the  eye. 

No  one  acquainted  with  the  most  elementary  laws  of 
optics  will  have  any  difficulty  in  understanding  why  the 
pupil  appears  black,  and  why,  without  special  instru- 
ments, we  are  unable  to  look  into  the  interior  of  an 
eye.  As  in  the  camera  obscura,  the  refracting  system 
of  the  eye,  which  is  a  double  lens  consisting  of  the  cornea 
and  aqueous  humor,  throws  a  reduced  inverted  image  on 
the  retina.  This  image  appears  sharply  outlined  if  the 
eye  is  properly  focussed  for  the  object,  and  blurred — that 
is  to  say,  in  diffusion  circles — when  the  eye  is  not  prop- 
erly focussed,  just  as  in  the  photographic  camera. 


DESCRIPTION  OF  THE  OPHTHALMOSCOPE.        19 

Now  we  learn  from  one  of  the  laws  of  the  refraction 
of  lenses  that  object  and  image  bear  a  definite  relation  to 
each  other — they  are  said  to  be  reciprocal  or  conjugate — 
so  that  they  may  be  interchanged  without  necessitating 
any  alteration  in  the  dioptric  system  or  in  the  distances 
from  the  lens  to  the  object  and  to  the  image.  If  in  a 
dark  room  we  obtain  on  the  disk  of  ground  glass  a  clear 
image  of  a  candle  held  at  a  distance  of  one  meter  in  front 
of  the  object-lens,  and  then  put  the  light  in  the  place  of 
the  ground  glass,  we  will  get  a  clear  image  of  the  flame 
by  holding  the  ground  glass  where  the  light  originally 
was,  that  is  to  say,  one  meter  in  front  of  the  lens.  In 
other  words,  we  may  reverse  the  positions  of  the  candle 
and  of  the  ground  glass,  and  in  each  case  obtain  a  sharp 
image  of  the  candle,  providing  we  retain  the  original  dis- 
tances— in  the  former  case  behind,  and  in  the  latter  in 
front  of  the  lens.  The  rays  of  light  emitted  by  the  image 
on  the  ground  glass,  after  leaving  the  apparatus,  all  return 
to  the  flame  of  the  candle.  But  as  our  eyes  do  not  send 
out  any  rays  of  light  when  we  look  into  a  dark  chamber, 
they  cannot  receive  any  rays  in  return  ;  hence  the  open- 
ing of  the  camera  and  the  object-lens  appear  dark,  and 
in  the  same  way  the  opening  of  the  eye  into  which  we  are 
looking ;  in  other  words,  the  pupil  also  appears  dark. 

If,  however,  rays  of  light  are  sent  out  from  the  ob- 
server's eye,  the  rays  which  enter  the  observed  eye  return 
to  the  eye  of  the  observer,  and  the  pupil  of  the  observed 
eye  appears  red  like  that  of  an  albino.  Before  the  inven- 
tion of  the  ophthalmoscope  an  erroneous  theory  was  cur- 
rent that  the  pigment  of  the  fundus  absorbed  all  the  light 
that  enters  the  eye,  and  the  {)upil  of  a  pigmented  eye  there- 
fore appeared  black.  If  the  eye-ground  of  a  normal  eye 
is  illuminated  by  rays  emerging  from  the  observer's  eye, 
'enough  rays  will  be  reflected  by  the  eye-ground,  which 
even  in  a  pigmented  eye  is  not  entirely  black,  to  enable 
the  observer  to  get  a  clear  image  of  the  other  eye.  On 
the  other  hand,  the  pupil  of  an  albino  is  red,  not  because 
of  any  want  of  pigment  in  the  fundus,  but  because  of  the 


20  OPHTHALMOSCOPY. 

absence  of  pigment  in  front,  so  that  the  rays  of  light  pass 
through  the  iris,  sclera,  and  choroid,  and  illuminate  the 
eye  at  every  point  instead  of  only  at  the  focus  of  the  re- 
flecting media.  In  such  eyes  there  is  no  reciprocal  rela- 
tion between  the  object  and  the  image ;  the  rays  emerge 
from  the  pupil  in  all  directions,  and  the  latter  appears  in 
a  red  light  because  the  eye-ground  of  the  albino  (in  man, 
in  the  white  rabbit,  etc.)  is  colored  red  by  the  numerous 
blood-vessels  of  the  choroid.  If  in  the  albino  the  light 
is  prevented  from  entering  the  eye  in  this  abnormal  way 
through  the  unpigmented  tissues  outside  the  pupil,  and 
the  pupil  is  then  examined,  it  will  appear  as  dark  as  in 
the  ordinary  individual.  This  can  be  done  by  holding 
immediately  in  front  of  the  albino's  eye  an  opaque  cup 
with  an  opening  corresponding  in  size  to  the  pupil.  If 
the  light  is  allowed  to  enter  only  through  this  opening 
and  through  the  pupil,  the  latter  will  appear  as  black 
as  that  of  a  pigmented  eye. 

Now  we  can  by  means  of  any  simple  device,  and  best 
by  means  of  the  ophthalmoscope,  send  out  light  from  our 
own  eye.  Even  an  ordinary  glass  disk  held  in  front  of 
the  eye,  by  virtue  of  its  reflecting  qualities,  w^ill  direct 
into  the  eye  the  rays  emanating  from  a  light  standing  to 
one  side.  If  the  light  is  placed  to  the  left  of  the  person 
examined,  and  the  glass  disk  is  turned  slightly  toward 
the  lamp,  so  that  the  reflection  of  the  light  falls  on  the 
observed  eye,  the  pupil  wall  immediately  a])pear  red  when 
seen  through  the  piece  of  glass  (cf.  Fig.  A).  As  the  rays 
coming  from  the  lamp  {L)  are  in  part  reflected  into  the 
observed  eye  by  the  glass  disk,  they  enter  it  in  such  a 
way  that  they  appear  to  come  from  a  point  behind  the 
observer's  eye,  that  is,  from  the  point  X2,  which  would 
correspond  to  the  reflected  image  of  the  lamp.  Since 
they  enter  the  observed  eye  they  illuminate  the  eye- 
ground.  If  the  eve  is  focussed  for  the  distance  of  the 
reflected  image  of  the  lamp,  a  clear  image  of  the  lamp 
will  be  produced  on  the  fundus ;  but  if  the  eye  is  not 
focussed  for  this  distance,  the  image  will  be  blurred.     In 


DESCRIPTION  OF  THE  OPHTHALMOSCOPE.        21 

any  case  a  certain  portion  of  the  eve-ground  of  the  ob- 
served eye  is  illuminated  and  thereby  enabled  to  send 
back  rays  of  light.  These  rays  return  to  the  object — in 
this  case  the  flame  of  the  lamp.  As  the  disk  of  glass 
not  only  reflects  but  also  transmits  light,  a  portion  of  the 
rays  returning  from  the  observed  eye  pass  through  the 
glass  and  enter  the  observer's  eye,  while  the  remainder 
are  reflected  toAvard  the  lamp  and  lost  to  the  observer. 

But  the  amount  of  light  entering  the  observer's  eye  in 
this  way  is  very  slight  and  the  illumination  of  the  pupil 


Fig.  a. — Illumination  of  the  eye  luuler  examination  iVn.)  by  means 
of  the  glass  disk,  GL;  two  of  tlie  rays  coming  from  a  point  in  the  light 
(L)  are  shown  ;  one  of  these  rays,  after  being  reflected  by  the  glass  plate, 
misses  the  eye;  part  of  the  other  ray  passes  through  the  glass  {Gl.)  and  is 
lost  to  the  observer  (5^.),  while  the  remainder  is  reflected  into  the  eye  of 
the  person  examined  {Un.),  returns  by  the  same  path,  and  enters  the  eye 
of  the  observer  in  the  direction  of  L-i,  the  reflected  image  of  the  eye  ;  S,  S, 
perpendiculars  to  Gl. 

of  the  observed  eye  correspondingly  weak.  The  light 
may  be  increased  by  adopting  Helmholtz's  plan  of  laying 
several  glass  disks  one  upon  the  other,  but  even  with  such 
an  arrangement  the  amount  of  light  entering  the  observer's 
'eye  is  comparatively  small.  A  much  better  result  is  ob- 
tained by  throwing  more  light  into  the  observed  eye,  so 
that  the  eye-ground  is  more  powerfully  illuminated  and 
accordingly  sends  back  more  light,  and,  secondly,  by 
allowing  the  returning  rays  to  enter  the  observer's  eye 


22  OPHTHALMOSCOPY. 

without  being  weakened  ;  that  is  to  say,  tlirough  a  hole 
in  the  mirror. 

Accordingly,  Helmholtz's  disks  were  soon  replaced  by 
a  true  mirror  which  throws  much  more  light  into  the  eye. 
By  scraping  away  the  coating  from  a  small  spot  in  the 
center  an  opening  was  obtained  for  the  returning  rays  to 
enter  the  observer's  eye.  The  amount  of  liglit  entering 
the  eyes,  both  of  the  observed  and  of  the  observer,  may 
be  still  further  increased  by  using  a  concave  mirror  which 
concentrates  the  light  before  throwing  it  into  the  observed 
eye,  and  by  making  an  actual  opening  at  the  center  of 
the  mirror,  so  that  the  returning  rays  meet  with  even  less 
resistance  in  their  passage  through  the  mirror. 

By  thus  illuminating  the  eye  with  the  rather  weak 
Helmholtz  ophthalmoscope,  or  better,  with  the  somewhat 
stronger  but  still  comparatively  weak  plane  mirror,  or, 
best  of  all,  with  a  powerful  concave  mirror,  we  can 
obtain  a  distinct  view  of  the  otherwise  invisible  eye- 
ground.  As  the  illuminated  fundus  sends  out  rays  of 
light  which  enter  the  observer's  eye  in  the  manner  ex- 
plained, it  is  evident  that  the  observer  obtains  in  his  own 
eye  a  clear  image  of  the  eye-ground  observed.  The  fun- 
dus of  the  observed  eye  is  converted  into  a  luminous 
object  which  we  can  see  like  any  other  object  in  the  out- 
side world.  Strictly  speaking,  however,  we  see  the  eye- 
ground  as  we  see  an  object  through  a  magnifying  glass, 
the  reflecting  media  of  the  observed  eye  forming  a  lens 
through  which  we  see  the  individual  portions  of  the  eye- 
ground  under  a  high  magnification.  Some  persons  require 
additional  aids  to  obtain  a  clear  view  of  the  eye-ground 
by  the  method  just  described. 

This  method  of  examination  is  known  as  the  direct 
method  or  the  method  loith  the  erect  image.  It  is  called 
the  direct  method  because  it  enables  a  normal  eye  to 
examine  another  normal  or  hypermetropic  eye  without 
any  additional  aids.  It  is  called  the  examination  with 
the  erect  image  because  we  see  the  eye-ground  right  side 
up  like  any  other  object  in  the  outer  world. 


EXAMINATION  IN  THE  ERECT  IMAGE.  23 

I.  EXAMINATION  IN  THE  ERECT  IMAGE. 

Without  certain  devices  to  alter  the  direction  of  the 
rays  of  light  emerging  from  the  patient's  eye,  this 
method  of  examination  is  often  impossible,  and  this 
brings  us  to  a  further  and  very  important  feature  of 
ophthalmoscopic  examination. 

It  appears  that  the  ophthalmoscope  not  only  enables 
us  to  see  the  things  ^vhich  are  to  be  seen  in  the  eye- 
ground,  but  also  furnishes  us  with  the  means  of  accurately 
measuring  the  refracting  power  and  the  structure  of  the 
observed  eye ;  and  these  data  are  most  valuable,  since 
they  are  entirely  objective  and  render  us  independent  of 
the  patient's  statements.  To  do  this  we  use  our  own  eye, 
the  refractive  system  of  the  eye  examined,  and  possibly 
certain  convex  or  concave  lenses,  and  thus  calculate  in 
the  simplest  possible  manner  the  optical  power  of  the 
observed  eye. 

To  understand  this  it  is  necessary  first  to  consider  the 
manner  in  which  the  entering  rays  leave  the  eye  in  the 
case  of  a  normal,  a  myopic,  and  an  hypermetro])ic  organ. 

As  has  been  explained  above,  the  rays  of  light  always 
return  to  the  point  from  which  they  have  come  and  on 
which  the  eye  is  therefore  focussed — in  the  above  exam- 
ple the  flame  of  a  candle  fixed  at  a  distance  of  one  meter 
in  front  of  the  eye.  In  this  case  the  eye  is  accommodated 
for  the  distance  of  one  meter.  An  emmetropic  eye  Avith- 
jout  accommodation  is,  of  course,  focussed  for  infinity ; 
Ithat  is  to  say,  for  parallel  rays.  The  fundus  of  such  an 
eye,  therefore,  reproduces  a  clear  image  of  all  objects 
'sending  out  parallel  rays  of  light ;  in  other  words,  of  all 
distant  objects.  As  the  diameter  of  the  pupil  is  very 
small,  an  object  may  be  considered  distant  if  it  is  3  to  5 
meters  away  from  the  eye;  that  is  to  say,  the  error  of 
considering  rays  coming  from  such  a  point  as  parallel 
rays  is  infinitesimally  small.  When,  therefore,  an  em- 
metropic eye  looks  into  infinity  or  looks  at  an  object 
3    to   5    meters   away,    the    rays   of   light    leaving   the 


24  OPHTHALMOSCOPY. 

illuminated  eye-ground  also  return  to  infinity  and  are 
therefore  parallel  (cf.  Fig.  C).  It  follows  that  if  we 
examine  an  emmetropic  eye  by  the  above-described  direct 
method,  the  rays  of  light  emerging  from  the  eye  imme- 
diately form  a  clear  image  of  the  fundus  on  the  observer's 
eye,  providing  the  observer  also  looks  into  infinity ;  in 
other  w^ords,  adjusts  his  eye  to  parallel  rays.  If  the 
observer  accommodates  instead  of  looking  into  infinity, 
he  will  obtain  a  blurred  image  of  the  observed  eye- 
ground;  but  as  in  order  to  look  into  an  eye  one  has 
to  get  as  near  to  it  as  possible,  just  as  when  looking  into 
a  room  through  a  key-hole,  it  is  somewhat  difficult  to 
relax  the  accommodation.  This  is  one  of  the  greatest 
difficulties  encountered  by  the  beginner  in  attempting  to 
examine  by  the  direct  method. 

It  is,  however,  absolutely  indispensable  if  he  wishes  to 
obtain  a  correct  measurement  of  the  refraction  of  the 
observed  eye ;  in  other  words,  the  observer's  eye,  in 
order  to  measure   the   refraction   of  another   eye,   must 

!  relax  its  accommodation  completely,  because  it  is  impos- 
sible to  calculate  the  increase  in  the  refractive  power  of 

!  the  observer's  eye  due  to  the  accommodation.  We  can 
measure  our  own  accommodation  only  when  we  know  for 
what  distance,  that  is  to  say,  for  what  degree  of  diver- 
gence of  the  rays  entering  our  own  eye,  it  is  focussed ;  but 
the  very  object  of  an  examination  by  the  direct  method 
is  to  determine  the  divergence  of  the  rays  of  light  which 
leave  our  own  eye. 

It  follows  from  what  has  been  said  that  the  observer 
must  know  the  exact  refractive  power  of  his  own  eye  in 
order  to  be  able  to  measure  that  of  the  patient's  eye.  If 
the  observer  is  emmetropic,  he  gets  a  clear  image  of  the 
eye-ground  of  the  patient's  eye  without  any  further  ap- 
pliances. If  he  is  myopic,  he  will  obtain  a  blurred 
image,  as  everything  that  sends  out  parallel  rays,  or  in 
other  words,  is  at  an  infinite  distance  from  his  eye, 
appears  blurred.  To  see  distant  objects  the  myope 
needs  spectacles  with  concave  lenses ;  hence  to  examine 


EXAMINATION  IN  THE  ERECT  IMAGE.  25 

by  the  direct  method  the  myope  must  also  use  a  correct- 
ing glass,  which  he  places  behind  the  opening  in  the  oph- 
thalmoscope, if  he  wishes  to  obtain  a  clear  image  of  the 
eye-ground  of  the  emmetropic  eye. 

If  the  observer  is  hypermetropic,  he  is  in  the  same 
position  when  he  attempts  to  examine  by  the  direct 
method  as  when  he  looks  into  infinity;  he  must,  since 
his  eye  is  not  focussed  for  parallel  rays,  either  wear  a 
correcting  glass  with  convex  lenses  or  accommodate. 
But  as  he  is  not  allowed  to  resort  to  the  latter  expe- 
dient, he  must,  during  the  examination,  use  a  glass 
which  completely  corrects  his  hypermetropia.  His  hy- 
permotropia  must  be  completely  corrected,  so  that  he 
may  not  be  forced  to  compensate  for  some  unknown 
degree  of  hypermetropia  by  using  his  accommodation. 
This  is  particularly  difficult  for  the  hypermetrope,  be- 
cause he  has  become  so  accustomed  to  correct  his  optical 
error  by  accommodating  that  he  finds  it  very  difficult  to 
substitute  a  correcting  lens  for  his  power  of  accommoda- 
tion. He  continues  to  accommodate  even  when  looking 
through  the  correcting  lens — at  least  to  some  extent — and 
is  accordingly  over-corrected.  This  is  particularly  the 
case  in  high  grades  of  hypermetropia  when  the  individual 
is  young  and  the  power  of  accommodation  is  well  pre- 
served. 

Surgeons  with  moderate  hypermetropia  are,  therefore, 
often  compelled  to  resort  to  some  other  means  of  meas- 
uring the  refraction  if  they  do  not  wish  to  depend  on  the 
patient's  statement — either  to  Schmidt-Rimpler's  method 
by  means  of  the  inverted  image,  or  to  the  shadow-test. 
These  two  methods  will  be  discussed  later. 

We  have  assumed  up  to  this  point  that  the  person 
examined  is  emmetropic  and  that  the  observer  is  emme- 
tropic, myopic,  or  hypermetropic.  What  is  the  condition 
of  affairs  when  it  is  desired  to  examine  an  eye  with  ab- 
normal refraction?  We  must  first  determine  in  what 
way  the  rays  emitted  by  an  illuminated  eye-ground  leave 
the  eye  in  the  case  of  myopia  or  hypermetropia.     Again, 


2S  OPHTHALMOSCOPY. 

we  assume  that  the  ametropic  eye  under  examination  looks 
into  infinity,  so  that  the  accommodation,  which  we  cannot 
compute,  may  be  disregarded  in  the  calculation.  The 
patient,  whether  he  be  emmetropic  or  ametropic,  must 
always  relax  his  acconamodation  while  his  refraction  is 
being  taken. 

Measurement  of  the  Myopic  Eye. 

A  myopic  eye,  when  it  is  not  accommodating,  is 
focussed  for  a  point  at  a  finite  distance,  depending  on 
the  degree  of  myopia.  This  point  is  known  as  the /ar 
point  (punctum  remotum).  It  is  the  farthest  point  at 
which  an  eye  of  this  kind  sees  distinctly.  Only  those 
rays  which  come  from  this  point  are  collected  on  the 
retina  and  form  there  a  distinct  image,  when  the  eye  is 
looking  into  infinity  without  accommodating.  Rays  com- 
ing from  a  more  remote  point  are  focussed  in  front  of 
the  retina,  and  the  image  formed  on  the  retina  is  blurred. 
The  reason  that  the  image  is  formed  in  front  of,  instead 
of  on  the  retina,  as  in  the  normal  eye,  is  usually  that  the 
myopic  eye  is  too  long  (cf.  Fig.  D)  or  that  the  refracting 
power  of  the  lens  is  too  great.  Excessive  length  of  the 
eyeball  is  the  chief  cause  of  myopia.  In  order  to  see 
distant  objects  distinctly,  the  myopic  eye  must  be  corrected 
by  means  of  a  concave  lens  which  weakens  the  refraction, 
so  that  the  entering  rays  are  focussed  on  the  retina,  behind 
the  focus  of  the  lens. 

Let  us  now  consider  how  the  rays  emanating  from  an 
illuminated  portion  of  the  eye-ground  in  a  myopic  eye 
leave  the  eye  after  traversing  the  refractive  media  in  the 
contrary  direction.  If  the  eye  docs  not  accommodate, 
they  will  tend  to  converge  at  the  far  point  (cf.  Fig.  D), 
since  the  far  point  is  at  a  finite  distance  from  the  eye 
(«',  6',  plane  of  the  far  point).  If  the  far  point  is  situ- 
ated at  a  distance  of  one  meter  from  the  eye,  the  degree 
of  myopia  is  equivalent  to  a  lens  of  one-meter  focus 
(diopter),  and  the  error  in  such  a  case  is  corrected  by 
means  of  a  lens  having  a  focal  distance  of  one  meter.  If 
the  far  point  is  situated  at  0.5  meter  from  the  eye,  the 


EXAMINATION  IN  THE  ERECT  IMAGE. 


27 


error  is  twice  as  great  and  the  correcting  glass  must  be 
twice  as  strong ;  that  is,  a  glass  equivalent  to  two  meter- 
lenses  or  diopters  ;  or,  in  other  words,  a  lens  having  a 


Fig.  B 


Fig.  C. 


Figs.  B,  C,  D. — Examination  in  the  erect  image  when  the  eye  exam- 
ined is  hypermetropic,  emmetropic,  or  myopic.  In  each  figure  three  rays 
are  shown  emanating  from  a  luminous  point  on  the  eye-ground.  In 
hypermetropia  they  diverge  after  leaving  the  eye,  in  emmetropia  they 
are  parallel,  in  myopia  they  converge :  /,  the  posterior  focus ;  H,  prin- 
cipal plane  of  the  dioptric  system  of  the  examined  eye  ;  £e.,  observer. 
The  ophthalmoscope  is  not  shown. 


focal  distance  of  0.5  meter.  If  the  distance  of  the  far 
point  is  \  meter  =  25  cm.,  the  degree  of  myopia  is  four 
times  as  great  =  4  diopters,  and  the  correcting  glass  must 


28  OPHTHALMOSCOPY. 

have  a  focal  length  of  \  meter  =  25  cm.,  etc.  In  the  last 
case,  for  instance,  the  myopia  is  corrected  by  a  concave 
lens  of  4  D  (with  a  focal  distance  of  25  cm.),  because 
such  a  glass  when  held  immediately  in  front  of  the  eye 
renders  parallel  rays  coming  from  infinity  so  divergent 
that  they  appear  to  come  from  the  far  point  of  the 
eye,  which  is  at  a  distance  of  25  cm. ;  for  a  concave 
lens  of  4  D  lends  such  a  degree  of  divergence  to  entering 
parallel  rays  of  light  that  they  seem  to  come  from  the 
focus  of  the  lens  {=  25  cm.). 

It  follows,  therefore,  that  the  rays  of  light  leaving  a 
myopic  eye  converge  to  the  far  point.  If,  therefore,  a 
normal  eye  is  placed  behind  the  ophthalmoscope  it  will 
not  see  anything  of  the  eye-ground,  since  it  is  not  focussed 
for  converging  rays  of  light,  for  converging  rays  do  not 
occur  in  nature  without  a  special  cause.  The  examiner's 
eye,  therefore,  requires  an  additional  lens  behind  the  oph- 
thalmoscope of  such  a  strength  as  completely  to  correct 
the  myopia  of  the  examined  eye ;  or,  in  other  words,  to 
render  parallel  the  rays  which  emerge  from  the  examined 
eye,  since  the  normal  eye  is  focussed  for  parallel  rays  of 
light.  The  degree  of  myopia  of  the  examined  eye  can, 
therefore,  be  found  in  this  way  l)y  selecting  the  weakest 
concave  lens  with  which  it  is  possible  to  get  a  distinct 
image  of  the  fundus.  The  weakest  concave  lens  must  be 
selected  so  as  to  eliminate  the  examiner's  own  accommo- 
dation, for  he  could  see  quite  distinctly  with  a  stronger 
concave  lens,  because  his  power  of  accommodation  would 
enable  him  to  neutralize  the  excessive  concavity  of  the 
lens. 

If  the  observer  is  myopic,  he  will  need,  in  order  clearly 
to  see  the  fundus  of  another  myopic  person,  a  concave 
lens  strong  enough  to  correct  both  his  own  and  the  other's 
myopia.  If,  for  example,  he  finds  that  a  lens  of  5  D  is 
the  weakest  lens  with  which  he  can  see  the  eye-ground 
clearly,  and  if  he  himself  has  a  myopia  of  two  diopters, 
the  examined  eye  has  a  myopia  of  3  D. 

If,  on  the  other  hand,  the  observer  is  hypermetropic 


EXAMINATION  IN  THE  ERECT  IMAGE.  29 

to  an  extent,  let  us  say,  of  two  diopters  and  finds  the 
correcting  concave  lens  to  be  one  of  5  D,  he  must  add 
his  own  hypermetropia,  and  the  patient's  eye  in  that  case 
has  a  myopia  of  7  D.  An  emmetropic  observer  in  this 
case  would  need  a  concave  lens  of  7  T>,  but  the  hyper- 
metrope  needs  one  of  only  5  D,  because  his  own  correct- 
ing convex  glass  of  2  D  neutralizes  the  effect  of  a  con- 
cave glass  of  2  D.  He  would  also  need  —  7  if  he  looked 
through  the  ophthalmoscope  with  his  own  correcting  lens 
of  2  D.  But  it  is  better  to  have  only  one  lens  behind 
the  ophthalmoscope,  hence  he  will  need  only  —  5  instead 
of  —  7  to  correct  the  myopia  of  the  examined  eye. 

Measurement  of  the  Hypermetropic  Eye. 

Having  now  considered  cases  where  the  examined  eye 
is  either  emmetropic  or  myopic,  we  must  consider  the 
possibility  of  its  being  hypermetropic. 

Again,  we  must  consiclor  how  the  rays  of  light  emerge 
from  an  hypermetropic  eye  when  it  is  illuminated  with  the 
ophthalmoscope.  An  hypermetropic  eye  without  accom- 
modation is  focussed  neither  for  parallel  nor  for  diver- 
gent, but  for  convergent  rays  of  light  (cf.  Fig.  B) ;  that 
is  to  say,  only  convergent  rays  of  light  are  collected  on 
the  retina  to  form  a  distinct  image.  Parallel  rays  of 
light  entering  the  eye  unite  to  form  an  image  behind 
the  retina  at  the  point  /,  either  because  the  axis  of  the 
hypermetropic  eye  is  too  short  or  because  its  refractive 
system  is  too  weak,  as,  for  instance,  when  the  lens  is 
absent.  In  either  case  the  refractive  system  of  the  hy- 
permetropic eye  is  insufficient  as  compared  with  its 
axis,  and  therefore  requires  a  re-enforcing  lens.  The 
hypermetropic  eye  can,  by  exerting  its  accommodation, 
increase  its  refractive  power  by  increasing  the  refrac- 
•tion  of  the  lens,  so  as  to  bring  the  image  forward  and 
on  to  the  retina.  It  differs  from  the  emmetropic  eye  in 
the  fact  that  it  has  to  accommodate  even  when  looking 
into  infinity,  but  this  can  be  obviated  by  the  use  of  a  con- 
vex lens.     As  a  rule,  the  visual  error  in  the  hyperme- 


30  OPHTHALMOSCOPY. 

tropic  eye  is  only  partially  corrected  by  a  lens,  the  indi- 
vidnal  correcting  the  remainder  himself.  In  fact,  it  is 
impossible  in  yonthfiil  snbjects,  whose  power  of  accom- 
modation is  vigorous,  to  find  the  degree  of  hypermetropia 
by  means  of  correcting  lenses.  Such  persons  always 
accommodate  more  or  less  when  they  fix  an  object,  and 
they  will  accept  only  a  convex  glass  which  corrects  a 
portion  of  their  hypermetropia.  This  portion  is  called 
the  manifest  hypermetropia  of  the  individual,  while  that 
portion  which  is  corrected  and  concealed  by  the  accom- 
modation is  known  as  the  latent  hypermetropia.  As  the 
individual  grows  older  and  the  poAver  of  accommodation 
diminishes,  the  manifest  hypermetropia  increases.  If  the 
accommodation  is  entirely  removed,  either  by  age  or  by 
a  drug  (atropin,  homatropin),  the  total  hypermetropia  be- 
comes evident. 

The  examination  in  the  erect  image  furnishes  a  very 
convenient  method  of  determining  an  individual's  total 
hypermetropia  without  artificially  paralyzing  the  accom- 
modation ;  for  if  the  hypermetrope,  even  though  he  be 
young,  does  not  focus  his  eyes,  but  looks  into  the  distance 
in  the  dark  room,  he  will  not  accommodate  during  the 
examination  with  the  ophthalmoscope,  and  the  rays  of 
light  leaving  the  eye  will  follow  the  direction  given  them 
by  the  structure  of  the  media  ;  that  is  to  say,  they  diverge. 
The  degree  of  divergence  is  proportional  to  the  degree  of 
hypermetropia  and  inversely  proportional  to  the  distance 
of  the  negative  far  point  behind  the  eye.  If  the  hyper- 
metropia is  such  that  the  eye  is  focussed  only  for  rays 
which  converge  at  a  point  0.5  meter  behind  the  principal 
plane  of  the  eye,  the  error  is  corrected  by  a  convex  lens 
having  a  focal  distance  of  0.5  meter,  or  a  lens  of  2  D.  The 
hypermetropia  is  2  D.  If  in  order  to  be  collected  on  the 
retina  the  rays  require  a  greater  degree  of  convergence, 
for  example,  to  a  point  only  25  cm.  behind  the  principal 
plane  of  the  eye ;  in  other  words,  if  the  far  point  is  25 
cm.  (—  1  meter)  behind  the  eye,  the  error  is  twice  as  great. 
The  hypermetropia  is  4  D,  and  the  correcting  lens  must 


EXAMINATION  IN  THE  ERECT  IMAGE,  31 

be  of  equal  strength,  unless  the  individual  when  looking 
into  infinity  accommodates  to  the  extent  of  4  D.  A 
lens  of  +  4  D  held  in  front  of  such  an  eye  will,  there- 
fore, give  to  the  rays  coming  from  infinity  the  necessary 
degree  of  convergence  ;  for  a  convex  lens  of  4  D,  held 
immediately  in  front  of  the  eye,  refracts  parallel  rays 
entering  the  eye  in  such  a  w^ay  that  they  converge  toward 
the  focus  of  the  lens  —  25  cm.,  which  is  also  the  far  point 
of  the  eye,  as  we  may  disregard  the  distance  from  the  lens 
to  the  principal  plane  of  the  eye. 
'  //  The  same  correcting  lens  will  render  the  divergent  rays 
'^<yemerging  from  the  eye  parallel,  since  they  come  from  the 
/  focus  of  the  lens.  Approximately  the  same  result  is 
obtained  by  holding  the  correcting  lens  behind  the  open- 
ing in  the  ophthalmoscope.  An  observer  with  normal 
vision  looking  into  such  an  liypermetropic  eye  will  be 
able  to  see  the  fundus  distinctly.  He  could,  of  course, 
see  it  without  a  correcting  lens,  but  only  by  using  his 
accommodation  to  the  extent  of  4  D  in  the  present  exam- 
ple, which  would  be  a  source  of  error  in  obtaining  the 
measurement  of  the  eye. 

If  the  observer  himself  is  hypermetropic,  he  must 
combine  his  own  correcting  lens  with  that  required  by 
the  examined  eye.  To  determine  the  error  of  the  exam- 
ined eye  he  must  subtract  his  own  correcting  lens  from 
the  convex  lens  used.  It  is  best  in  this  case  to  use  the 
strongest  lens  with  which  the  fundus  can  be  seen  dis- 
tinctly, so  as  to  avoid  neutralizing  a  certain  portion  of 
the  hypermetropia  by  one's  own  accommodation. 

If,  on  the  other  hand,  the  observer  is  myopic,  he  needs 
a  weaker  correcting  lens  than  does  the  observer  with 
normal  vision,  because  his  own  error  neutralizes  the  error 
of  the  examined  eye.  If,  for  instance,  the  observer's  eye 
is  focussed  for  the  rays  coming  from  a  distance  of  20  cm. 
(myopia  5  D),  his  eye  without  accommodation  is  focussed 
for  rays  eaierging  from  the  eye  of  an  hypermetrope  of  5  D, 
and  he  therefore  needs  no  glass.  The  hypermetropia  of 
the  patient's  eye  in  such  a  case  is  equivalent  to  the  exam- 


32  OPHTHALMOSCOPY. 

iner's  myopia.  If  the  observer  requires  a  convex  lens 
he  must  add  to  the  value  of  this  lens  the  number  of 
diopters  of  his  own  myopia.  If,  for  instance,  his  myopia 
amounts  to  3  D  and  he  needs  a  +  2  D  lens  to  see  the 
fundus,  the  patient  has  an  hypermetropia  of  5  D.  If  a 
myope  of  7  D  needs  only  a  —  3  D  lens,  the  patient  has 
an  hypermetropia  of  4  D. 

The  beginner  in  ophthalmoscopy  should  always  re- 
member (cf.  Figs.  B,  C,  D)  that  rays  emerging  from  an 
emmetropic  eye  are  parallel,  those  from  a  myopic  eye 
convergent,  and  those  from  an  hypermetropic  eye  diver- 
gent; and,  conversely,  that  the  examining  eye  without 
accommodation  is  focussed  for  parallel  rays  of  light  if  it 
is  emmetropic ;  for  divergent  rays,  if  it  is  myopic ;  and 
for  convergent  rays,  if  it  is  hypermetropic. 

From  what  has  been  said  we  may  deduce  the  following 
general  rules  : 

If  in  order  to  see  distinctly  the  eye-ground  of  another's 
eye  an  ametrope  needs — 

(1)  A  lens  of  the  same  kind  as  that  which  corrects  his 
own  ametropia,  but  of  a  greater  strength,  he  must  sub- 
tract the  number  of  his  own  diopters  from  the  diopters 
of  the  lens  used. 

(2)  If  the  required  lens  is  of  the  same  kind,  but  from 
1  to  10  diopters  weaker  than  that  which  corrects  his  own 
ametropia,  the  refractive  error  of  the  examined  eye  is  of 
the  contrary  kind  and  amounts  to  from  1  to  10  diopters. 
(Examples :  If  the  observer  has  a  myopia  of  6.0  and 
needs  —  5.0,  the  eye  examined  has  an  hypermetropia  of 
1.0.  If  the  observer  needs  a  4.0,  the  eye  examined  has 
an  H.  of  2.0,  etc.  If  the  observer  has  an  H.  of  4.0  and 
needs  a  +3.0,  the  eye  examined  has  a  M.  of  1.0,  etc.) 

(3)  If  the  required  lens  is  of  the  contrary  kind  from 
that  required  to  correct  the  observer's  ametropia,  the  eye 
examined  has  the  contrary  refraction,  and  the  amount  of 
the  error  will  be  equal  to  the  number  of  diopters  of  the 
required  lens  jplus  the  number  of  diopters  of  the  ob- 


EXAMINATION  IN  THE  ERECT  IMAGE.  33 

server's  correction,  it  being  immaterial  whether  the  lens 
found  is  stronger  or  weaker  than  the  examiner's  own  lens. 
Examples  :  If  the  examiner  has  M.  5.0  and  needs  a  +  3.0 
lens,  the  patient  has  an  liypermetropia  of  8.0.  But,  if  the 
examiner  has  H.  3.0  and  needs  a  —4.0  lens,  the  patient 
has  a  myopia  of  7.0.  If  the  examiner  has  H.  3.0  and 
needs  a  —2.0  lens,  the  patient  has  a  myopia  of  5.0.  If 
the  examiner  has  M.  3.0  and  needs  a  -f5.0  lens,  the  patient 
has  an  hypermetropia  of  8.0. 

The  refraction  can  be  deterujined  even  more  rapidly  in 
the  erect  image  by  means  of  a  simple  formula  based  on  the 
fact  that  the  strength  of  the  k^ns  found  with  the  ophthal- 
moscope— (Sp) — is  equal  to  the  sum  of  the  ametropia  of 
the  examiner  (A)  and  that  of  the  patient  (x).  Hence  the 
formula  : 

Sp  =  A  +  X. 

Hence,  if  the  examiner's  ametropia  is  deducted  from  the 
strength  of  the  lens  found  with  the  ophthalmoscope  (Sp), 
the  remainder  is  the  patient's  ametropia  : 

Sp  —  A  =  X. 

In  carrying  out  this  subtraction  it  must  be  remembered 
that  the  subtraction  of  a  negative  quantity  is  equivalent  to 
addition. 

EXAMPLES. 

Ophtalrao-      Examiner's  PnipniafinTi  Patient's 

scopiclens       ametropia  ^-tticumuuii  ametropia 

(Sp).  (A).  Sp-Ax.  (X). 

+  5D.  2D.  H.  (+2)  (+5)  — (+2)*=       5-2=  +3  -i- 3  (2  D.  Hyp.) 

-1-5D.  2D.  M.  (-2)  +5)  — (-2)=       5  +  2=  +7  +  7  (7  D.  Hyp.) 

-  5  D.  2D.  M.  (-  2)  (_  5)  —  (—  2)  =  —  5  +  2  =  —  3  -  3  (3  D.  My.) 

-5D.  2D.  H.  (+2)  (_5)-(+2)=  — 5  — 2-  — 7  —  7  (7  D.  Mv.) 

+  2  D.  5  D.  H.  (+  5)  (+  2)  -  (+  5)  =       2  —  5  =  -  3  —  3  (3  D.  My. ) 

-2D.  5  D.  M.  (-  5)  (_  2)  -  (—  5)  =  —  2  +  5  =  +  3  +3  (3  D.  Hyp.) 

'  In  order  to  be  accurate  in  determining  the  refraction 
of  an  eye  the  following  points  must  be  observed  :  The 
dioptric  conditions  of  that  portion  of  the  eye-ground 
which  corresponds  to  the  point  of  clearest  vision — viz., 
the  macula  lutea  or  fovea  centralis  of  the  retina — must 


34  OPHTHALMOSCOPY. 

be  determined.  Hence  in  measuring  the  refraction  of 
an  eye  the  examiner  must  obtain  a  good  view  of  that 
portion  of  the  eye-ground.  Now  the  macula  lutea  is  the 
most  difficult  portion  to  see,  because  when  we  attempt  to 
examine  it  the  pupil  contracts  and  the  reflection  of  the 
light  on  the  cornea  is  most  disturbing. 

Besides,  it  is  not  very  easy  to  determine  whether  the 
image  is  clear  when  we  look  into  the  macula  lutea, 
because  there  is  a  lack  of  conspicuous  markings,  the 
retinal  vessels  being  at  this  point  extremely  small.  All 
that  can  be  seen  is  a  fine  stippling  of  the  eye-ground 
due  to  the  somewhat  variable  amount  of  pigmentation 
of  the  cells  forming  the  pigmented  epithelium  of  the 
retina.  The  darker  the  eye-ground,  the  more  uniform 
it  usually  appears  and  the  more  difficult  it  is  to  focus 
accurately.  It  is  true  that  in  dark  eye-grounds,  espe- 
cially in  young  individuals,  a  small  bright  sickle  or  ring 
is  seen,  due  to  the  reflection  of  the  light  at  the  bottom 
of  the  fovea  centralis,  and  although  this  reflex  is  a  little 
in  front  of  the  retina,  the  difference  is  so  slight  that  it 
need  not  be  considered  in  calculating  the  refraction.  If 
the  fovea  reflex  is  too  indistinct  to  be  utilized  in  this 
way,  it  is  best  to  look  for  the  vessels  which  pass  from 
the  optic  nerve  toward  the  macula  lutea  or  for  a  vessel 
coming  from  above  or  below  and  running  toward  the 
macula. 

The  beginner  will  do  well  to  confine  himself  to  the 
tem]ioral  margin  of  the  optic  disk,  as  it  is  more  clearly 
outlined,  and  the  presentee  of  blood-vessels  which  pass 
over  it  toward  the  macula  (cf.  Figs.  1,  4,  etc.)  makes  it 
possible  to  obtain  measurements  in  the  various  meridians. 
In  this  way  the  so-called  astigmatism  of  the  eye  can  also 
be  measured. 

Measurement  of  Astigmatism. 

The  term  astigmatism,  is  applied  to  an  abnormal  refrac- 
tive condition  of  the  eye  in  which  one  or  more  of  the 
refractive  surfaces,  instead  of  being  spherical  or  slightly 


EXAMINATION  IN  THE  ERECT  IMAGE.  35 

parabolic,  have  a  greater  curvature  iu  one  meridian  than 
in  the  meridian  at  ri^ht  angles  to  it.  When  a  pencil  of 
rays  diverging  from  a  luminous  point  impinges  on  a  re- 
fractive surface  with  an  equal  curvature  in  all  its  merid- 
ians, as,  for  instance,  a  hemisphere  like  one  of  our  glass 
lenses,  the  rays  are  all  united  in  one  point,  disregarding 


Fig.  E. — Eefractive  surface,  with  a  greater  curvature  in  the  vertical  than 
in  the  horizontal  meridian. 

those  which  strike  the  lens  too  near  the  margin,  known 
as  marginal  rays.  But  if  the  pencil  of  rays  impinges 
on  a  surface  having  a  weaker  curvature  in  the  hori- 
zontal than  in  the  vertical  meridian  (cf.  Fig.  E),  the  rays 
passing  through  the  vertical  meridian  are  more  strongly 
refracted  than  those  passing  through  the  horizontal. 
Hence  the  former  rays  are  brought  to  a  focus  at  a  })oint 
nearer  the  refractive  surface  than  are  the  latter.  The 
surface  has  two  foci,  and  rays  emanating  from  a  lumin- 
ous point  ('^  homocentric"  pencil)  are  not  united  at  any 
one  point  behind  the  refracting  surface,  hence  the  name 
astigmatism  (d,  privative ;  rb  ariyaa,  the  point). 

As  every  point  on  the  object  must  have  a  correspond- 
ing point  in  the  image  in  order  that  a  clear  image  may 
be  produced,  it  follows  that  an  astigmatic  surface  can 
produce  only  a  distorted  image.  Hence  the  image  on 
^he  retina  of  an  astigmatic  eye  will  be  distorted  whether 
the  abnormal  curvature  is  in  the  lens  or  in  the  cornea ; 
and,  conversely,  when  such  an  eye  is  examined  with  the 
ophthalmoscope,  the  markings  on  the  eye-ground  (optic 
disk,  vessels  of  the  retina,  etc.)  appear  blurred  and  can- 
not be  brought  out  clearly  with  any  additional  spherical 


36  OPHTHALMOSCOPY. 

lens.  A  lens  with  a  curvature  in  only  one  direction — a 
so-called  cylindrical  lens — is  required.  A  lens  with  no 
curvature  in  the  vertical,  and  a  corresj)onding  positive 
curvature  in  the  horizontal  meridian  will,  in  the  above 
example  (see  Fig.  E),  correct  the  abnormally  weak  hori- 
zontal curvature  of  the  refracting  surface.  Some  ophthal- 
moscopes permit  of  the  use  of  such  cylindrical  lenses, 
but  they  are  not  absolutely  necessary  for  the  measure- 
ment of  astigmatism.  With  a  little  practice  it  is  usually 
quite  possible  to  measure  the  refraction  for  every  indi- 
vidual meridian.  [Dr.  B.  Alex.  Randall  has  designed  an 
ophthalmoscope  which  carries  a  disk,  by  means  of  which 
cylindrical  lenses  can  be  rotated  behind  the  sight-hole, 
which  is  of  great  practical  value. — Ed.] 

The  student  should  remember  that  the  vertical  meridian 
of  a  spherical  or  sphericocylindrical  (astigmatic)  lens 
corrects  the  horizontal  and  not  the  vertical  lines  of  the 
object,  while  the  horizontal  meridian  corrects  the  vertical 
and  not  the  horizontal  lines.  If,  therefore,  the  horizontal 
vessels  running  from  the  optic  disk  toward  the  macula 
are  seen  distinctly,  it  shows  that  the  refraction  of  the 
vertical  meridian  of  the  refractive  system  has  been  cor- 
rectly determined.  Another  glass  will  be  required  to 
obtain  a  clear  image  of  the  vertical  lines  (those,  for  in- 
stance, that  run  into  the  macula  from  above  or  below), 
or  of  the  temporal  margin  of  the  optic  disk  which  at  one 
point  is  approximately  vertical.  This  glass  corresponds 
to  the  refraction  of  the  horizontal  meridian  of  the  refrac- 
tive system. 

It  happens  sometimes  that  the  principal  meridians 
intersect  each  other  obliquely  instead  of  at  a  right  angle. 
In  that  case  the  use  of  a  certain  lens  will  enable  the 
observer  to  see  the  vessels  running  outward  and  upward 
near  the  optic  nerve,  while  those  which  run  outward  and 
downward  appear  quite  indistinct.  To  see  the  latter 
another  glass  will  be  required,  with  which  again  the 
vessels  running  outward  and  upward  will  appear  in- 
distinct.     In   measuring  the  astigmatism    it   is   of   the 


EXAMINATION  IN  THE  ERECT  IMAGE.  37 

greatest  importance  that  both  the  examiner  and  the 
patient  relax  their  accommodation. 

Care  must  also  be  taken  not  to  look  through  the  lens 
obliquely.  This  should  always  be  avoided  as  much  as 
possible,  otherwise  the  observer  might  discover  astig- 
matism where  none  is  present,  or  even,  under  certain 
conditions,  correct  astigmatism  without  knowing  it ;  for 
by  looking  obliquely  through  an  ordinary  spherical  lens 
we  get  the  effect  of  an  unequal  refraction  exactly  similar 
to  the  regular  astigmatism  now  under  discussion. 

We  also  speak  of  irregular  astigmatism.  This  occurs 
when  a  refractive  surface  has  an  irregular  curvature,  as, 
for  instance,  when  the  surface  is  uneven.  The  image  in 
this  case  is  blurred  and  cannot  be  made  distinct  for  any 
length  of  time  by  any  means  in  our  power.  Irregular 
astigmatism  is  usually  due  to  inequalities  in  the  surface 
of  the  cornea  corresponding  to  more  or  less  marked 
opacities.  These  defects  in  the  cornea  can  usually  be 
recognized  by  means  of  lateral  illumination. 

Finally,  in  measuring  refraction  with  the  ophthal- 
moscope by  the  direct  method,  the  distance  between 
the  observer's  eye  and  that  of  the  patient  must  be 
considered. 

It  should  always  be  as  short  as  possible,  otherwise  the 
correcting  lens  of  the  ophthalmoscope  is  too  for  removed 
from  the  eye  examined,  and  its  refractive  power  is  altered. 
The  power  of  a  concave  lens  is  lessened  by  increasing  its 
distance  from  the  eye  ;  and,  conversely,  a  convex  lens  is 
more  powerful  when  placed  at  a  greater  distance  from 
the  eye,  which  explains  why  old  people  often  push  their 
spectacles  down  to  the  tip  of  the  nose  to  make  them 
stronger. 

This  error  requires  correction  in  strong  lenses,  but 
may  be  disregarded  in  weak  glasses,  especially  as  the 
spectacles  to  be  ordered  will  always  be  worn  at  some 
distance  from  the  eye. 

In  using  strong  lenses  it  is,  therefore,  always  to  be 


38  OPHTHALMOSCOPY. 

borne  in  mind  that  the  correcting  lenses  found  with  the 
ophthahnoscope  will  be  too  strong  in  myopia  and  too 
weak  in  hypermetropia,  if  the  observer's  eye  is  too  far 
away  from  the  eye  examined.  In  such  a  case,  therefore, 
the  myopia  of  the  eye  examined  is  weaker  and  the 
hypermetropia  stronger  than  the  lens  in  the  ophthal- 
moscope. 

Size  of  the  Ophthalmoscopic  Field  of  Vision. 

Another  reason  for  coming  as  close  as  possible  to  the 
eye  under  examination  is  that  it  is  easier  in  that  way  to 
look  into  the  eye  through  the  comparatively  narrow  pupil. 
By  coming  as  close  to  the  pupil  as  possible  the  observer 
is  able  to  see  a  larger  portion  of  the  eye-ground  without 
changing  the  relative  positions  of  his  own  and  the  patient's 
eye  ;  in  other  words,  the  ophthalmoscopic  field  of  vision  is 
increased.  If  the  pupil  is  very  small,  it  must  be  dilated 
either  by  shielding  the  other  eye  from  the  light,  or  by 
means  of  drugs — homatropin  in  2  per  cent.,  or  euphthal- 
min  in  5  per  cent,  solutions.  From  2  to  3  drops  instilled 
within  five  minutes  usually  suffice  to  produce  the  desired 
amount  of  dilatation  within  twenty  minutes.  The  use 
of  atropin  for  this  purpose  is  to  be  avoided  as  much  as 
possible,  as  its  action  lasts  too  long  and  may  produce 
increased  intraocular  tension  (glaucoma),  especially  in 
elderly  people.  [No  mydriatic  is  entirely  free  from  the 
danger  of  producing  glaucoma;  even  euphthalmin  has 
caused  this  disease,  witness  a  case  reported  by  Knapp. 
Euphthalmin  mydriasis  may  be  neutralized  by  the  instilla- 
tion of  a  pilocarpin  solution  (gr.  j-f5J)  before  the  patient 
is  dismissed. — Ed.] 

An  experienced  observer  will  very  rarely  need  to  dilate 
the  pupil  artificially  in  a  normal  eye  unless  he  particularly 
wishes  to  examine  the  macular  region.-  For  this  purpose 
artificial  dilatation  is  often  indispensable,  especially  in 
elderly  people,  who  usually  have  smaller  pupils  than 
young    persons.       For   similar   reasons    the    opening    in 


EXAMINATION  IN  THE  ERECT  IMAGE.  39 

the  ophthalmoscope  should  not  be  too  small.  The 
most  desirable  width  is  3.5  mm.  [Some  surgeons 
prefer  a  smaller  opening — e.  (/.,  Jackson  recommends 
that  the  aperture  in  the  mirror  shall  be  2  mm.  in  diam- 
eter.— Ed.] 

The  size  of  the  ophthalmoscopic  field  further  depends 
on  the  refraction  of  the  eye  under  examination.  It  is 
greatest  in  hypermetropia,  because,  as  we  have  seen,  the 
rays  diverge  after  leaving  the  eye;  smaller  in  emmetropia ; 
and  still  smaller  in  myopia,  because  the  emerging  rays 
converge. 

Another  factor  that  influences  the  size  of  the  ophthal- 
moscopic field  in  the  direct  method  is  the  size  of  the  flame 
used  in  the  examination,  particularly  when  a  strong  con- 
cave mirror  is  used,  one,  for  instance,  with  a  focal  dis- 
tance of  16  cm.,  which  is  also  employed  in  the  indirect 
method,  soon  to  be  discussed.  With  a  mirror  of  this 
kind  one  often  gets  an  inverted  image  of  the  flame 
on  the  eye-ground  while  everything  else  is  indistinct. 
Beginners  will,  therefore,  do  well  not  to  use  too  small 
a  flame. 

If  it  is  desired  to  illuminate  a  very  large  field  a  con- 
cave mirror  with  a  very  short  focal  distance  may  be  used. 
This  third  mirror,  however,  complicates  the  instrument 
unnecessarily. 

This  brings  us  to  the  choice  of  a  mirror  in  the  direct 
method.  Besides  tlie  strong  concave  mirror  just  described, 
which  is  best  for  beginners,  we  may  select  either  a 
plane  mirror  or  a  concave  mirror  of  about  16  cm.  focal 
distance,  which  is  also  used  in  the  indirect  method.  The 
latter  is  decidedly  to  be  preferred  in  the  examination  of 
the  macular  region,  which  on  account  of  its  dark  color 
usually  reflects  very  little  light.  The  macula  is  not  suf- 
ficiently illuminated  by  the  plane  mirror,  although  the 
latter  has  the  advantage  of  not  contracting  the  pupil  quite 
so  much. 


40 


OPHTHALMOSCOPY. 


II.  EXAMINATION  BY  THE  INDIRECT  METHOD. 

This  method,  first  proposed  by  Riite,  consists  in  illumi- 
nating the  eye-ground  by  means  of  a  concave  mirror  and 
holding  a  strong  convex  lens  (13-20  D)  at  the  near 
point;  that  is  to  say,  at  a  focal  distance  of  5  to  7.5  cm. 
from  the  patient's  eye,  so  as  to  imite  the  rays  of  light  as 
they  emerge  from  the  eye  and  produce  a  true  inverted 
image  (cf.  Fig.  F.  To  save  room  the  lens  and  the  eye 
of  the  observer  are  shown  somewhat  nearer  the  patient's 
eye  than  they  ought  to  be).  In  this  method  the  observer 
sits  at  a  greater  distance  from  his  patient,  and  sees  the 


Emelr 


Fig.  F. — Examiuation  of  an  emmetropic  eye  by  the  indirect  method : 
the  parallel  rays  of  light  coming  from  the  eye  are  focussed  by  the  lens 
(/.),  and  form  a' true  inverted  image  which  is  directly  seen  by  the  observer 
(£e.) ;  a,  principal  plane;  My.  and  Hy.,  the  respective  points  where,  in 
myopia  and  hypermetropia,  the  inverted  image  is  formed.  The  oph- 
thalmoscope is  not  shown. 

inverted  image  very  distinctly  by  looking  through  the 
opening  in  the  ophthalmoscope.  As  he  must  use  his  ac- 
commodation to  see  the  image,  he  must  be  at  a  distance 
of  25  to  30  cm.  [This  accommodative  strain  may  be 
relieved  and  the  image  magnified  by  placing  behind  the 
ophthalmoscope  a  convex  glass  of  4  D,  which  adapts  the 
emmetropic  observer  with  relaxed  accommodation  for  a 
point  25  cm.  distant. — Ed.] 

In  high  degrees  of  myopia  the  observer  can  in  this 
way  obtain  an  inverted  image  of  the  eye-ground  without 
the  aid  of  an  additional  lens,  as  may  be  seen  in  Fig.  D 


EXAMINATION  BY  THE  INDIRECT  METHOD.      41 

(p.  27) ;  for  the  rays  emerging  from  a  myopic  eye  converge 
to  such  an  extent  that  they  form  a  true  inverted  image 
at  the  far  point.  Hence,  if  on  simply  ilhmiinating  the 
eye  and  looking  through  the  hole  in  the  mirror  an  in- 
verted image  of  the  vessels  or  part  of  the  optic  nerve  is 
clearly  seen  within  the  red  glare  of  the  pupil,  we  may 
conclude  that  we  have  to  deal  with  a  high  degree  of 
myopia.  To  determine  whether  the  image  of  the  eye- 
ground  seen  in  the  pupil  is  an  inverted  or  erect  one, 
the  observer  notes  whether  the  vessels  in  the  pupil  move 
in  the  same  or  in  the  contrary  direction  as  he  turns  liis 
head  from  side  to  side.  This  point  must,  however,  be 
very  carefully  investigated  before  a  diagnosis  of  myopia 
is  made,  as  it  is  possible  by  simply  throwing  the  light 
into  the  eye  from  a  certain  distance  to  see  a  partial  erect 
image  in  the  pupil.  It  occurs  when  the  eye  under  exam- 
ination has  a  high  degree  of  hypermetropia  and  is  due 
to  the  fact  that  the  rays  diverge  after  leaving  the  eye  (as 
shown  in  Fig.  B).  But,  owing  to  the  great  distance  of 
the  eye  under  examination,  the  visual  field  is  very  small, 
only  a  small  portion  of  the  eye-ground  is  seen,  and  the 
image  in  the  pupil  moves  in  the  same  direction  as  the 
observer's  head. 

With  the  aid  of  a  convex  lens  it  is  possible  to  obtain 
an  inverted  image  in  any  eye,  that  is  to  say,  any  eye  may 
be  made  to  appear  like  a  myopic  eye,  but  the  distance  of 
the  inverted  image  from  the  auxiliary  lens  varies  with 
the  refractive  conditions.  If  the  eye  under  examination 
is  emmetropic,  the  emerging  rays  of  light  arc  parallel  and 
the  inv^erted  image  is  found  in  the  focal  plane  of  the 
auxiliary  lens ;  in  myopia  the  image  will  be  nearer  the 
lens  (for  instance,  at  My.  in  Fig.  F),  and  in  hypermetropia 
farther  away  than  the  focus  (for  instance,  at  Hif.  in  Fig.  F). 
Hence,  if  the  observer  does  not  alter  his  accommodation, 
he  has  to  move  his  head  back  when  he  examines  an 
eye  with  a  high  degree  of  hypermetropia.  As  a  rule, 
however,  it  is  better  to  accommodate.  The  distance  of 
the  auxiliary  lens  [often  called  the  supplementary  lens 


42  OPHTHALMOSCOPY. 

or  object  glass]  from  the  plane  of  the  pupil  of  the  ex- 
amined eye  should  be  approximately  equal  to  its  focal 
distance.  In  this  way  the  pupil  and  the  iris  disappear 
completely  and  nothing  but  an  image  of  the  eye-ground 
is  seen  in  the  entire  domain  of  the  convex  lens.  The 
larger  the  glass  the  wider  the  view  of  the  eye-ground 
obtained  ;  hence, 

The  Size  of  the  Visual  Field  ^ 

in  the  indirect  method  depends  chiefly  on  the  size  of  the 
auxiliary  lens,  and  to  some  extent  on  the  refraction  of  the 
eye  under  examination  and  the  focal  distance  of  the  aux- 
iliary lens.  The  higher  the  degree  of  myopia  of  the  eye 
under  examination,  the  greater  the  ophthalmoscopic  field; 
the  higher  the  degree  of  hypermetropia,  the  smaller  the 
ophthalmoscopic  field.  The  nearer  the  auxiliary  lens  is 
brought  to  the  eye,  that  is  the  stronger  the  auxiliary  lens, 
the  greater  the  number  of  rays  emerging  from  the  eye  it 
can  receive  and  the  greater,  therefore,  the  visual  field. 
Finally,  as  in  the  direct  method,  the  size  of  the  visual 
field  depends  on  the  size  of  the  area  illuminated  by  the 
ophthalmoscope.  A  greater  portion  of  the  eye-ground  is 
illuminated  in  the  indirect  than  in  the  direct  method ;  the 
illumination  is  also  more  powerful,  as  a  concave  mirror  is 
generally  used  in  this  method.  The  size  of  the  pupil 
does  not  affect  the  size  of  the  visual  field  so  much  in  the 
indirect  as  in  the  direct  method ;  in  other  words,  the  eye- 
ground  can  be  seen  quite  distinctly  even  when  the  pupil 
is  very  small,  although,  of  course,  a  contracted  pupil  cuts 
off  a  great  deal  of  the  light  and  the  image  may,  therefore, 
become  very  indistinct  if  the  pupil  is  too  small. 

To  sum  up,  it  may  be  said  that  the  indirect  method 
has  the  following  advantages  over  the  direct  method:  1. 
Greater  distance  from  the  eye  under  examination,  making 
the  examination  less  irksome  for  both  the  patient  and  the 
surgeon  ;  2.  A  larger  visual  field,  so  that  a  much  greater 

[^  "  Gesichtsfeld  "  is  the  word  used  ;  in  English  text-books  simply  the 
word  "field"  is  usually  employed. — Ed.] 


EXAMINATION  BY  THE  INDIRECT  METHOD.      43 

area  of  the  fundus  can  be  examined  at  one  time ;  3.  Cor- 
recting lenses  on  the  ophthalmoscope  can  be  dispensed 
with ;  4.  The  examination  is  possible  even  when  the 
pupil  is  contracted.  On  the  other  hand,  with  the  indi- 
rect method  one  sees  the  eye-ground  under  a  lower 
magnifying  power,  and  this  is  the  principal  diiference 
between  the  two  methods. 


Enlargement  of  the  Image  in  the  Direct  and  in  the 
Indirect  Method. 

The  size  of  the  image  obtained  by  the  direct  method 
depends  on  several  conditions :  1.  The  refraction  of  both 
patient  and  surgeon  ;  2.  The  distance  between  the  eyes  of 
patient  and  surgeon  ;  3.  The  distance  between  the  cor- 
recting glass  and  the  eye  under  examination.  v.  Helm- 
holtz^  and,  later,  Mauthner"^  calculated  the  magnification 
for  emmetropic  eyes  and  found  it  to  be  one  of  14^  diam- 
eters. L.  Weiss  ^  obtained  approximately  the  same  re- 
sult— 15.6 — by  directly  measuring  a  dead  eye  that  had 
been  carefully  examined  in  this  respect  during  life. 

In  hypermetropia  the  size  of  the  image  is  smaller,  in 
myopia  larger,  than  in  emmetropia,  provided  that  the 
correcting  lens  is  placed  at  a  distance  of  3  cm.  from  the 
eye  under  examination.  If  the  hypermetropia  is  due  to 
abnormally  weak  refractive  power,  as,  for  instance,  to 
aphakia,  the  image  is  smaller  than  in  hypermetropia  due 
to  shortening  of  the  axis,  just  as  it  is  smaller  in  myopia 
due  to  the  lengthening  of  the  axis  than  in  myopia  due  to 
abnormally  strong  refractive  power  of  the  refracting  sys- 
tem (Mauthner,  loc,  cit.,  p.  185). 

In  hypermetropia  the  size  of  the  image  is  smaller  when 
the  correcting  lens  is  at  a  greater  distance  from  the  exam- 
iiTed  eye,  and,  conversely,  the  image  is  larger  in  myopia 

^  V.   Helmholtz,    Handbuch    der  Physiologischen   Optik,   second  edition, 
p.  217. 

^  Mauthner,  Lehrbuch  der  Ophthahnoskopie,  p.  177. 
'  L.  Weiss,  Arch.  f.  Ophthalmoloyie,  vol.  xxiii. 


44  OPHTHALMOSCOPY. 

when  tlie  leus  is  at  a  greater  distance  from  the  eye 
(Mauthner,  loc.  cit.). 

In  the  indirect  method  the  size  of  the  image  depends 
chiefly  on  the  strength  of  the  auxihary  lens  ;  that  is,  the 
stronger  the  lens,  the  smaller  the  image  and  the  greater 
the  visual  field.  According  to  v.  Helmholtz  (loc.  dt., 
p.  218),  if  we  take  Listing's  schematic  eye  as  a  basis,  we 
obtain  a  magnification  of  3  diameters  with  an  auxiliary 
lens  of  22  D  (focal  distance  45  mm.),  and  a  magnification 
of  4  diameters  with  a  lens  of  16.6  D  (focal  distance,  60 
mm.).  The  refraction  of  the  eye  under  examination  also 
has  some  influence  on  the  size  of  the  image.  In  hyper- 
metropia  the  magnification  is  somewhat  greater,  and,  con- 
versely, in  myopia  it  is  somewhat  weaker.  According  to 
Mauthner  {loc.  cit.,  p.  230),  the  magnification  is  greater 
in  hypermetropia  due  to  diminution  in  the  length  of  the 
axis  than  in  hypermetropia  due  to  diminished  refractive 
power  of  the  dioptric  system  ;  and,  conversely,  the  mag- 
nification is  less  in  myopia  due  to  lengthening  of  the  axis 
than  in  myopia  due  to  abnormally  strong  refractive  power 
of  the  dioptric  system.  Whereas,  therefore,  in  the  direct 
method  the  fundus  appears  appreciably  modified,  that 
is  under  12-14-20  diameters,  the  magnification  is  only 
from  2-4—8  diameters  in  the  indirect  method  with  a 
convex  lens  of  17  D,  which  is  the  most  suitable  for  this 
method. 

On  the  other  hand,  the  indirect  method,  as  has  been 
stated,  offers  the  advantage  of  a  larger  visual  field,  hence 
it  follows  that  to  obtain  a  general  idea  of  the  conditions 
in  as  short  a  time  as  possible  it  is  best  to  examine  first  by 
the  indirect  method,  and  if  it  is  desired  to  make  a  more 
accurate  study  and  to  measure  the  refraction,  an  exami- 
nation may  be  made  by  the  direct  method  which  shows 
the  eye-ground  under  a  greater  magnification.  [Students 
in  this  country  are  apt  to  neglect  indirect  ophthalmoscopy. 
This  is  unfortunate,  and  Haab's  advice,  to  employ  first 
the  indirect  and  then  the  direct  method,  is  sound  and 
should  be  followed. — Ed.] 


EXAMINATION  BY  THE  INDIRECT  METHOD.      45 

The  refraction  can  also  be  measured  by  the  indirect  method. 
The  method  devised  by  Schmidt-Rinipler '  is  the  best,  because 
the  observer  does  not  need  to  rehix  his  accommodation,  a  feat 
which  is  often  very  difficult,  especially  for  hypermetropic  eyes. 
The  position  of  the  inverted  image  of  the  eye-ground,  or,  in  other 
words,  the  distance  of  the  image  from  the  auxiliary  lens,  is  found 
(cf.  Fig.  F)  with  the  aid  of  a  special  apparatus.  In  this  connec- 
tion the  reader  should  recall  what  has  been  said  on  page  19. 
Rays  emanating  from  a  luminous  point  after  being  reflected  by 
the  eye  return  to  that  point  provided  the  eye  is  placed  in  proper 
relation  to  the  flame.  If,  therefore,  the  accommodation  is  relaxed, 
we  can  find  the  absolute  refraction  by  means  of  such  a  luminous 
point.  The  eye  is  first  rendered  myopic  by  means  of  a  strong 
convex  lens  placed  in  front  of  it,  so  that  the  emerging  rays  unite 
to  form  an  inverted  image  in  front  of  the  eye.  Thus,  for  exam- 
ple, in  emmetropic  eyes  a  lens  of  +  10.0  brings  the  image  10  cm. 
in  front  of  the  auxiliary  lens.  The  source  of  light  used  should 
not  be  an  actual  flame,  but  the  inverted  ophthalmoscopic  image 
of  a  flame  piaced  to  one  side  of  the  person  examined.  The  ob- 
server, looking  through  the  hole  in  the  ophthalmoscope,  alter- 
nately carries  the  instrument  backward  and  forward  until  the 
inverted  image  of  the  flame  appears  clearly  outlined  on  the  eye- 
ground.  When  this  point  is  reached  the  retina  and  the  image  of 
the  flame  correspond  to  conjugate  foci,  hence  the  image  of  the 
flame,  the  distance  of  which  from  the  ophthalmoscope  can  at  once 
be  measured,  coincides  with  the  far  point  of  the  examined  eye, 
providing  the  latter  is  looking  into  infinity,  or,  in  other  words, 
has  relaxed  its  accommodation.  By  determining  the  far  point  of 
a  myopic  eye  we,  at  the  same  time,  determine  its  refraction.  The 
accuracy  of  Schmidt-Rim])ler's  method  depends  on  the  absence 
of  accommodation  in  the  examined  eye.  This  is  not  readily 
accomplished  w'hen  the  image  of  the  flame  is  thrown  on  the 
macular  region,  or,  in  other  w^ords,  when  the  examiner — as  he 
ought  to  do — tries  to  measure  the  refraction  of  the  macular 
region.  If  we  do  not  paralyze  the  accommodation  of  the  exam- 
ined eye  by  means  of  a  drug,  we  are  forced  to  measure  the  refrac- 
tion of  the  retina  between  the  macula  and  the  optic  nerve. 

The  direct  as  well  as  the  indirect  method  further 
enables  us  to  determine  irregxdarities  in  the  surface  of 
the  eye-ground,  and  it  is  even  possible  to  measure  such 
inequalities  by  the  direct  method  if  the  observer  is 
skillful.     It  often  happens  that  the  head  of  the  optic 

1  Schmidt-Kim  pier,  Augenheilkunde  und  Ophthalmoskopie,  sixth  edition, 
p.  196. 


46  OPHTHALMOSCOPY. 

nerve  is  excavated,  so  that  instead  of  a  disk  we  have 
a  more  or  less  marked  depression.  The  opposite  condi- 
tion, in  which  the  head  of  the  nerve  projects  into  the 
eye,  is  equally  important.  And,  finally,  a  neoplasm  or 
a  foreign  body  on  the  eye-ground  may  project  into  the 
vitreous  body.  If,  then,  the  retina,  for  instance,  a})pears 
emmetropic,  the  floor  of  the  excavation,  being  further 
removed  from  the  refractive  system  of  the  eye,  will  show 
myopia.  If  the  retina  is  emmetropic  and  the  optic  nerve 
is  swollen  and  projects  into  the  globe,  the  summit  of  this 
prominence  will  show  hypermetropia,  because  the  dis- 
tance from  the  lens  at  that  point  is  diminished  (cf.  Fig. 
B,  p.  27),  or  the  retina  about  the  optic  nerve  may  show 
a  hypermetropia  of  5  D  and  the  floor  of  the  excavation 
M.  5.0,  in  which  case  there  is  a  difference  of  10  D  be- 
tween the  two  points,  w^hich  would  give  a  difference  in 
level  of  3.47  mm.  In  the  same  w^ay  it  might  be  possible 
to  measure  how  far  the  swollen  nerve-head  or  a  neoplasm 
projects  into  the  globe.  For  every  diopter  of  difference 
in  the  refraction  we  calculate  0.34  mm. 

In  the  indirect  method  inequalities  in  the  eye-ground 
are  determined  by  moving  the  convex  lens  in  front  of  the 
eye  from  side  to  side  without,  however,  for  a  moment 
losing  sight  of  the  eye-ground  or  of  the  optic  disk.  If 
the  nerve  is  excavated,  the  edge  of  the  excavation  moves 
in  front  of  the  floor  in  the  same  direction  as  the  convex 
glass.  If  the  head  of  the  nerve  projects,  the  summit  of 
the  prominence  moves  backward  and  forward  with  the 
auxiliary  lens ;  in  other  words,  a  plane  lying  nearer  the 
observer  moves  in  front  of  a  more  remote  plane  in  the 
same  direction  as  the  convex  lens.  This  phenomenon  is 
called  jxiralladic  displacement.  One  who  is  expert  in  ex- 
amining in  the  erect  image  can  take  advantage  of  the  proc- 
ess of  parallactic  or  perspective  displacement  to  determine 
inequalities  of  the  eye-ground.  The  examiner  approaches 
within  a  suitable  distance  of  the  eye  to  be  examined,  and, 
by  moving  his  head  to  and  fro,  recognizes  corresponding 
movements  of  objects,  which   occupy  various  planes.     In 


EXAMINATION  BY  THE  INDIRECT  METHOD.       47 

this  way  very  slight  differences  in  level,  such  as  a  hole  in 
the  center  of  the  retina,  can  be  recognized  in  the  eye-ground 
(Fig.  49). 

There  remain  to  be  mentioned  two  methods  of  examina- 
tion in  which  the  observer  also  sits  at  a  certain  distance 
from  the  eye  under  examination,  and  both  of  which  are 
also  performed  by  means  of  a  plane  mirror,  although  a 
concave  mirror  may  be  used. 

Examination  by  Transmitted  Light. 

This  procedure  is  very  simple,  but  none  the  less  im- 
portant. It  is  also  done  with  the  ophthalmoscope,  and 
should  precede  the  methods  described  so  far.  By  its  use 
ro  we  are  able  to  determine  : 

1.  Opacities  in  the  refractive  media — viz.,  the  cornea,  the 
aqueous  humor,  the  lens,  and  the  vitreous.  By  simply 
illuminating  the  eye  with  a  concave  or,  better,  a  plane 
mirror  and  looking  through  the  opening,  opacities  appear 
like  dark  shadows  in  the  red  pupillary  reflex,  because  the 
rays  of  light  as  they  return  from  the  eye-ground  are 
arrested  by  the  opacities,  just  as  all  opaque  objects,  even 
when  colored  white,  appear  dark  when  seen  in  front  of  a 
luminous  surface.  There  is  no  better  way  of  detecting  the 
whitish  opacities  produced  by  a  gray  cataract. 

(a)  In  the  corneal  region  this  method  reveals  not  only 
the  presence  of  opacities,  but  also  their  position  with  refer- 
ence to  the  pupillary  region,  which  determines  their  influ- 
ence on  the  visual  acuity  of  the  corresponding  eye.  For, 
if  the  examiner  requests  the  patient  to  look  him  straight 
in  the  eye,  he  can  accurately  recognize  by  transmitted 
light  how  much  a  corneal  opacity  diminished  the  trans- 
parency of  the  pupillary  region,  or,  in  other  words,  to  what 
extent  it  impairs  perfect  vision.  This  point  is  often  of 
iiTiportance  in  damage  cases. 

By  transmitted  light  the  finer  vessels  in  the  cornea,  which 
often  make  their  appearance  when  this  membrane  is  in- 
flamed, can  also  be  detected  far  better  than  by  any  other 
method,  for  they  appear  as  dark  lines  contrasting  sharply 


48  OPHTHALMOSCOPY. 

with  the  bright  pupillary  field.  The  procedure  is  partic- 
ularly useful  for  detectiug  the  broom-like  vessels  which 
persist  after  parenchymatous  keratitis.  These  vessels,  like 
the  punctate  deposits  which  will  presently  be  described, 
are  best  seen  with  a  magnifying  loupe.  For  this  purpose 
a  convex  lens,  8.0  to  16.0,  is  placed  behind  the  opening  in 
the  ophthalmoscope  (by  rotating  the  disk),  and  the  distance 
from  the  eye  to  be  examined  which  corresponds  to  the 
focal  distance  of  this  lens  is  found  by  advancing  and  re- 
treating until  the  corneal  vessels  and  other  structures  appear 
quite  faint. 

The  same  method  may  be  adopted  for  studying  the  im- 
portant deposits,  which  appear  in  iridocyclitis,  usually  on 
the  posterior  surface  of  the  cornea,  /.  c,  on  the  endothelium 
of  Descemet^s  membrane,  especially  in  the  lower  quadrant. 
In  studying  the  lower  segment  of  the  cornea  the  patient 
should  be  directed  to  glance  slightly  upward. 

The  adhesions  of  the  iris  to  the  lens  (synechise),  which 
are  caused  by  iritis  and  project  like  villi  into  the  pupil- 
lary region,  are  distinctly  seen  by  transmitted  light,  be- 
cause the  latter  is  usually  weaker  than  lateral  illumination, 
so  that  the  pupil  is  wider  and  the  villi  are  more  conspic- 
uous. 

(h)  Opacities  of  the  lens  must  be  carefully  scrutinized  by 
transmitted  light.  It  is  always  wrong  to  make  a  diagnosis 
of  beginning  gray  cataract  without  an  examination  by 
transmitted  light.  In  old  persons,  owing  to  the  physiologic 
sclerotic  changes  of  old  age,  the  lens  gives  a  fairly  well- 
marked  gray  reflex  by  daylight  or  under  lateral  illumina- 
tion, and  an  inexperienced  observer  often  makes  the  mis- 
take of  diagnosticating  ^'  gray  cataract."  In  such  cases 
examination  by  transmitted  light  at  once  shows  that  there 
are  no  genuine  cataractous  opacities,  which  most  frequently 
radiate  from  the  equator  of  the  lens  and  project  like  a 
phalanx  of  spears  or  wedges  into  the  pupillary  region.  (See 
Atlas  and  Epitome  of  External  Diseases  of  the  Eye,  third 
edition,  Plate  38.) 

Transmitted  light  is  also  very  well  adapted  for  exami- 


EXAMINATION  BY  THE  INDIRECT  METHOD.      49 

nation  of  an  opacity  at  the  posterior  pole  of  the  lens,  so- 
called  posterior  polar  cataract,  which  is  difficult  to  see  by 
direct  light  even  when  the  pupil  is  widely  dilated  and  the 
light  is  thrown  straight  into  the  eye.  The  opacity  is 
usually  circular  or  in  the  form  of  a  rosette.  The  fohowing 
points  should  be  remembered  in  locating  such  an  opacity  : 
If  with  transmitted  light  and  a  moderately  dilated  ])upil  a 
dark  opacity  is  seen  within  the  bright  pupillary  field,  svhile 
the  patient  looks  straight  before  him,  this  opacity  may  be 
situated  in  the  middle  of  the  cornea,  at  the  anterior  pole 
of  the  lens  or  at  the  posterior  pole  (or  possibly  even  in  the 
nucleus).  To  determine  the  exact  location  of  the  opacity 
the  patient  is  directed  to  glance  slightly  upward,  downward, 
to  the  right,  and  to  left.  When  the  eye  is  rotated  upward, 
a  central  corneal  opacity  will  move  upward  in  front  of  the 
pupil,  and  the  examiner  will  be  able  to  see  into  the  eye 
underneath  the  opacity.  But  if  there  is  an  opacity  at  the 
anterior  pole  of  tlie  lens,  as  happens  not  so  very  infre- 
quently, it  will  remain  in  the  middle  of  the  pupil,  move 
uj)ward  with  the  pupil,  and  obstruct  the  view  into  the  eye 
just  as  much  as  when  the  patient  looks  straight  before  him. 
If  the  opacity  is  situated  at  the  posterior  pole  of  the  lens, 
the  pupil  will  move  upward  in  front  of  it,  that  is  to  say,  the 
opacity  apparently  moves  downward  and  the  examiner  sees 
into  the  eye  over  the  top  of  the  opacity.  An  opacity 
situated  in  the  nucleus  also  descends  somewhat  when  the 
eye  is  rotated  downward. 

Transmitted  light  offers  the  surest  means  of  recognizing 
an  opacity  due  to  lamellar  cataract.  Since  the  examiner's 
object  is  to  determine  accurately  the  peripheral  circular 
outline  of  the  cataract,  the  pupil  often  has  to  be  dilated 
with  homatropin  ^  (or  euphthalmin)  and  inspected  while 
the  patient  glances  to  the  right,  to  the  left,  or  upward. 
By  this  method,  better  even  than  with  lateral  illumination, 
the  peripheral  border  of  the  cataract,  which  is  parallel  to 
the  equator  of  the  lens  and  at  a  varible  distance  from   it, 

^  Atropin  should  never  be  used  in  dilating  the  pupil  merely  for  pur- 
poses of  examination. 


50  OPIITHA  LMOSCOPY. 

can  be  accurately  determined.  (See  Atlas  and  Epitome  of 
ExternaUij  Visible  Diseases  of  the  Eye,  Plate  38.) 

(c)  Transmitted  light  is  especially  well  adapted  for  the 
detection  of  opacities  in  the  vitreous,  which  are  also  ex- 
ceedingly important.  Whereas  fixed  opacities  in  the 
refractive  media  move  with  these  media  when  the  eye  is 
rotated  in  various  directions,  freely  movable  opacities  in 
the  vitreous  continue  to  move  after  the  eye  has  come  to 
rest.  It  is  at  this  instance  that  the  examiner ,  must  care- 
fully look  for  any  shadows  that  may  be  moving  in  the 
bright  pupillary  field.  Such  shadows  are  produced  by 
shreds  of  tissue,  particles  of  exudate,  membranes,  and  the 
like  in  the  vitreous.  Diffuse  opacity  of  the  vitreous  can- 
not be  determined  by  this  method,  and  its  existence  can 
only  be  inferred  when  the  eye-ground  in  the  inverted  or 
erect  image  is  veiled,  and  lenticular  or  corneal  opacity  can 
be  excluded  from  the  etiology. 

Foreign  bodies  in  the  vitreous  are  detected  in  the  same 
manner  by  transmitted  light.  But  in  the  case  of  foreign 
bodies  the  patient  must  be  instructed  to  move  the  eye 
very  rapidly,  and  in  that  way  a  particle  of  iron  or  cop- 
per lying  immovable  and,  therefore,  invisible  on  the  floor 
of  the  vitreous  may  be  tossed  up  and  rendered  visible, 
even  if  only  for  an  instant.  Rotation  of  the  eye  in  vari- 
ous directions  must  be  kept  up  for  some  time,  until  finally 
the  foreign  body  is  tossed  up  from  the  bottom,  or  in  from 
the  side,  and  becomes  visible. 

Examination  with  transmitted  light  is  also  useful  as  a 
preliminary  method  in  the  detection  of  a  foreign  body  that 
is  fixed  somewhere  in  the  eye-ground,  and  may  be  usually 
recognized  by  its  somewhat  paler  color.  As  soon  as  the 
examiner's  line  of  vision  strikes  the  foreign  body  lying  in 
or  upon  the  retina  the  metallic  surface  throws  back  a  reflex 
which  illuminates  the  pupil,  unless  the  body  is  covered 
with  blood  or  exudates.  If  the  pupil  under  illumination 
appears  white,  instead  of  red  or  grayish  red,  the  convex 
lens  is  brought  into  use,  and  the  foreign  body  appears  "in 
the  inverted  image. 


EXAMINATION  BY  THE  INDIRECT  METHOD.      51 

2.  If  the  eye  is  examined  under  simple  direct  illumina- 
tion, marked  errors  of  refraction,  either  myopia  or  hyper- 
metropia,  can  be  detected  much  more  quickly  and  more 
easily  than  by  the  mensuration  methods  already  described, 
excepting  as  to  the  exact  number  of  diopters.  For  it  fol- 
lows from  what  was  stated  on  pages  41  and  42  that,  at  the 
distance  which  is  maintained  in  examining  in  the  inverted 
image,  structural  details  of  the  eye-ground  (blood-vessels 
and  the  like)  can  be  seen  in  the  illuminated  pupil,  in  the 
inverted  image  in  cases  of  high  myo])ia,  and  in  the  erect 
image  in  cases  of  marked  hypermetropia. 
o  High  degrees  of  myopia  can  even  be  measured  after  a 
fashion  by  this  method.  Thus,  the  examiner  gives  himself 
an  artificial  myopia  of,  say,  10  D.  by  using. a  suitable 
convex  lens.  If  he  is  emmetropic  he  holds  a  +10  D.  lens 
behind  the  ophthalmoscope ;  if  he  has  a  myopia  of  1  to  10 
D.  he  will  need  a  weaker  plus  lens,  one  that  will  bring  his 
myopia  up  to  10  (thus  with  a  myopia  of  3.0  he  will  only 
need  a  +7.0  lens).  If  the  examiner  is  hypermetropic  he 
must  add  his  total  hypermetropia  to  the  10  D.  Then, 
without  accommodating,  the  examiner  causes  the  image  of 
the  myopic  eye-ground,  which  appears  by  transmitted  light 
to  coincide  with  his  far  point  by  retreating  from  the  latter 
as  far  as  possible  without  making  the  image  appear  blurred, 
he  then  measures  the  distance  between  his  own  eye  and 
that  of  the  patient.  Suppose  this  distance  is  15  cm.; 
then  the  inverted  image  of  the  eye-ground  lies  10  cm. 
in  front  of  the  examiner's  and  5  cm.  in  front  of  the  patient's 
eye.  Hence,  the  patient's  far  point  is  at  a  distance  of  5 
cm.  or,  in  other  words,  he  has  a  myopia  of  20  D.  {^^^  =  20). 
Needless  to  say,  the  patient  must  not  accommodate  during 
the  examination.  The  inverted  image  of  the  eye-ground 
sometimes  coincides  with  the  patient's  as  well  as  with 
thS  examiner's  far  point ;  but  the  latter  artificially  changes 
the  distance  to  10  cm.,  so  that  the  calculation  can  be  based 
on  this  distance.  If  the  oculist  has  no  ophthalmoscope 
with  strong  concave  lenses  and  does  not  care  to  undertake 
the  shadow  test  (which  will  be  discussed  presently),  he 


52  OPHTHALMOSCOPY, 

can  determine  a  high  myopia  in  Iiis  patient's  eye  by  this 
method. 

Keratoconus  shows  itself  by  transmitted  light,  especially 
if  the  ophtluilmoscopic  mirror  is  moved  to  and  fro,  or  the 
mirror  reflex  in  the  pupil  is  carried  around  in  a  circle.  A 
circular  shadow  is  seen  in  the  bright  pupillary  field.  The 
same  occurs  when  the  lens  is  conical  posteriorly  (lenticonus 
posterior)  or,  what  is  more  frequent,  the  refractive  index 
of  the  nucleus  is  greater  than  that  of  the  cortex.  This 
condition  may  develop  during  old  age  and  cause  consider- 
able disturbance  of  vision. 

In  certain  cases  of  beginning  cataract  valuable  informa- 
tion may  be  obtained  by  examining  with  transmitted  light, 
especially  if  the  above-mentioned  genuine  opacities  have 
not  yet  developed,  and  vision  is  interfered  with  simply  by 
irregular  refraction  in  the  lens.  On  rotating  the  ophthal- 
moscope delicate  shadows  make  their  appearance  in  the 
bright  pupillary  field. 

3.  Transmitted  light  is  also  to  be  recommended  in  ex- 
amining the  interior  of  the  eye  for  the  presence  of  tumors, 
retinal  separation,  circumscribed  exudates,  and  the  like, 
occupying  the  anterior  half  of  the  vitreous.  The  examiner 
can  get  his  bearing  more  quickly  and  more  easily  by  this 
method  than  by  any  other  in  cases  of  this  kind.  A  sar- 
coma of  the  choroid  appears  as  a  dark  mass,  a  glioma  ap- 
pears bright,  abscess  causes  bulging  into  the  vitreous,  and 
the  same  picture  is  produced  when  a  large  retinal  separa- 
tion of  some  standing,  and  therefore  opaque,  causes  single 
or  multiple  prominences  in  the  anterior  portion  of  the 
vitreous.  Strictly  speaking,  Ave  are  dealing  with  an  erect 
image  in  these  cases.  The  vessels  belonging  to  the  retina, 
which  have  become  separated  by  the  sarcoma  or  in  some 
other  way,  are  seen  directly,  as  are  also  the  hemorrhages 
and  dilated  vessels,  which  are  so  frequently  present  on  the 
surface  of  a  glioma. 

So  long  as  a  large  retinal  separation  remains  transparent 
it  is  most  surely  detected  by  transmitted  light.  For  ex- 
ample, if  a  retinal  separation  of  this  kind  is  situated  on 


THE  SHADOW-TEST,   OR  SKIASCOPY.  53 

the  nasal  side,  the  beautiful  pink  brightness  of  the  pupil 
will  be  changed  to  a  peculiar  grayish  red  when  the  eye  is 
illuminated  from  the  nasal  side.  Secondly,  retinal  vessels 
will  be  seen  in  the  altered  pupillary  field  in  the  erect 
image,  recognized  by  the  fact  that,  when  the  observer 
moves  his  head,  they  move  in  tlie  same  direction.  This 
local  hypermetropia  of  the  retina  can  only  be  due  to  local 
diminution  of  the  distance  between  the  retina  and  the  re- 
fractive system  of  the  eye,  and,  therefore,  indicates  that  the 
membrane  is  displaced  or,  in  other  words,  that  there  is  a 
i^3  retinal  separation. 


THE  SHADOW=TEST,  OR  SKIASCOPY. 

The  discoverer,  Cuignet,  called  the  method  hcrntoscopy ; 
it  is  also  known  as  pupilloscopy  and  retinoscopy .  This 
method  of  examination  is  also  best  performed  with  the 
plane  mirror,  and  offers  the  easiest  means  of  determining 
the  refraction.  Retinoscopy  is  the  method  recommended 
for  any  one  who  is  unable  to  determine  refraction,  and 
especially  astigmatism,  by  the  direct  method  in  the  man- 
ner described,  if  he  does  not  care  to  use  Schmidt-Kimpler's 
apparatus.  It  also  requires  practice,  however,  and  is  not 
without  inconveniences.  In  retinoscopy,  as  in  Schmidt- 
Rimpler's  method,  the  object  is  to  determine  the  position 
of  the  far  point  of  the  eye  [point  of  reversal],  sometimes 
with  the  aid  of  a  convex  lens,  so  as  to  bring  the  far 
point  to  a  convenient  distance,  that  is,  between  the  ob- 
server and  the  patient.  This  is  especially  important  in 
low  degrees  of  myopia  and  in  hypermetro])ia.  The  far 
point  should,  if  possible,  be  brought  to  a  distance  of  20 
to  40  cm.  To  determine  the  optical  conditions  of  the 
ey^e  under  examination  by  this  method,  we  utilize  instead 
of  an  image  of  the  eye-ground  the  movement  of  the 
illuminated  portion  of  the  eye-ground  as  the  retinoscope 
is  moved  from  side  to  side.  The  retinoscope  illuminates 
a  certain  portion  of  the  eye-ground,  and  by  looking 
through  the  opening  the  observer  sees  a  corresponding 


54  OPHTHALMOSCOPY. 

movement  of  the  illuminated  portion  of  the  eye  under 
examination. 

Now  it  is  to  be  remembered  that  when  the  light  from  a 
flame  placed  to  one  side  of  the  patient  is  thrown  into  the 
eye  by  means  of  a  plane  mirror,  the  illuminated  portion 
of  the  eye-gronnd  moves  from  above  downward  if  the 
mirror  is  turned  from  above  downward,  or  it  moves  from 
right  to  left  if  the  mirror  is  turned  from  right  to  left. 
By  turning  the  mirror  from  right  to  left  we  mean  turn- 
ing it  as  if  we  wished  to  throw  light  into  the  right  and 
then  into  the  left  eye  of  the  person  examined. 

The  illuminated  portion  of  the  eye-ground  of  the  patienty 
therefore,  moves  in  the  same  direction  as  that  in  which  the 
plane  mirror  is  rotated,  or,  as  one  may  say,  "  with  "  the 
turning  of  the  mirror. 

If,  however,  the  eye  of  the  observer  is  beyond  the  far 
p)oint  of  the  eye  under  examination,  the  illuminated  field 
or  the  shadow  which  bounds  it  in  the  pupil  does  not  move 
in  the  same  direction  as  the  illuminated  portion  of  the 
eye-ground.  This  is  the  case  in  high  degrees  of  myopia, 
because  the  rays  emerging  from  the  eye  under  examina- 
tion converge  and  cross  each  other  at  the  far  point,  thus 
causing  the  shadow  to  move  in  the  contrary  direction. 
Hence  in  myopia  the  shadow  in  the  pupil  moves  in  a 
direction  contrary  to  that  of  the  mirror ;  that  is  to  say, 
if  the  mirror  is  turned  to  the  left,  the  shadow  moves  to 
the  right.  To  do  this  the  degree  of  myopia  must  be 
such  that  the  distance  of  the  far  point  is  less  than  the 
distance  of  the  ophthalmoscope  from  the  eye  under  ex- 
amination. If,  for  instance,  the  distance  between  the 
mirror  and  the  eye  under  examination  is  50  cm.,  and  the 
shadow  moves  in  the  opposite  direction,  there  must  be  a 
myopia  of  more  than  2  D  (-W"  =  2.0). 

Conversely,  the  illuminated  field  in  the  pupil  moves  in 
the  same  direction  as  the  mirror  when  the  examiner's  eye 
is  within  the  far  point  of  the  eye  under  examination  ; 
that  is  to  say,  in  a  low  degree  of  myopia  or  emmetropia, 
or  when  the  far  point  lies  behind  the  eye  under  examina- 


THE  SHADOW'TEST,   OR  SKIASCOPY.  55 

tion ;  in  other  words,  in  hypermetropia.  Under  these 
conditions  the  illuminated  field  moves  to  the  left,  for 
instance,  when  the  mirror  is  turned  to  the  left. 

On  the  other  hand,  if  the  position  of  the  observer's 
pupil  corresjwnds  exactly  with  the  far  point  of  the  eye 
under  examination,  the  illuminated  portion  of  the  pupil 
will  move  in  neither  direction  and  the  pupil  will  simply 
appear  alternately  dark  and  bright.  Whenever  this  phe- 
nomenon is  distinctly  seen  as  the  observer  alternately 
advances  and  recedes  from  the  ])atieiit,  the  distance  be- 
tween the  two  eyes  is  to  be  carefully  measured  with  the 
tape-measure.  The  result  corresponds  to  the  distance  of 
the  far  point,  and  thus  gives  the  refraction,  provided  that 
the  person  examined  has  relaxed  his  accommodation.  If, 
for  instance,  movement  disappears  at  a  distance  of  20  cm. 
between  the  observer's  eve  and  that  of  the  patient,  the 
latter  has  a  myopia  of  5.0  D  ( ^^  =  5.0). 

If  light  and  shadow  in  the  pupil  move  in  the  same 
direction,  the  observer  is  within  the  far  point,  and  he 
must  then  recede  until  the  movement  disappears  as  he 
turns  the  mirror  from  side  to  side,  or  he  may  place  a 
convex  lens  in  front  of  the  patient's  eye  so  as  to  bring 
the  far  point  within  a  convenient  measuring  distance,  as 
explained  above ;  that  is,  to  about  30  or  40  cm. 

In  choosing  this  auxiliary  lens  the  following  is  to  be 
borne  in  mind :  If  the  illuminated  field  in  the  pupil 
movies  in  the  same  direction  and  quickly,  and  the  con- 
cavity of  the  border  is  flat,  one  has  to  deal  Avith  a  low 
myopia,  an  emmetropia,  or  a  low  hypermetropia.  In 
such  a  case  a  weak  convex  lens  of  about  +  3  should  be 
selected.  If  the  illuminated  field  in  the  pupil  moves 
slowly  and  the  border  is  strongly  concave,  one  has  to 
deal  with  a  high  degree  of  hypermetropia.  A  strong 
convex  lens  is  then  selected,  which  must  be  allowed  for 
in  the  calculation.  If,  for  instance,  with  a  lens  of  +  7, 
the  far  point  is  found  at  33  cm.,  one  has  to  deal,  not  with 
a  myopia  of  3.0  ("VV'"^)?  ^^^'^  ^^^^^  ^'^  hypermetropia  of 
4.0,  because  it  is  evident  that  the  myopia  of  3.0  is  an 


56  OPHTHALMOSCOPY. 

artificial  myopia  produced  by  the  3  diopters  of  the  cor- 
recting lens,  and  the  remainder  of  4  diopters  would  re- 
move the  far  point  of  the  eye  under  examination  to 
infinity  and  thus  correct  its  error. 

The  shadow-test  can  also  be  carried  out  with  the  ordi- 
nary concave  mirror,  but  in  that  case  the  movements  of 
the  shadow  in  the  pupil  are  exactly  reversed  ;  that  is  to 
say,  the  shadow  moves  in  the  same  direction  when  the 
observer  is  beyond  the.  point  of  fixation,  and  in  the  con- 
trary direction  when  he  is  within  that  point,  or  when 
there  is  hypermetropia.  The  movement  of  the  shadow 
may  be  conveniently  observed  at  a  distance  of  1  meter 
and  20  cm.  from  the  patient.  If  the  shadow  moves  in 
the  same  direction  as  the  mirror,  there  is  myopia  of  one 
or  more  diopters.  The  eye  is  then  corrected  with  succes- 
sively stronger  concave  lenses  until  one  is  found  with 
which  the  movement  of  the  shadow  becomes  reversed. 
Such  a  glass  removes  the  far  point  of  the  eye  under  ex- 
amination to  beyond  1  meter  (1  diopter),  and  tlie  last  lens 
{a  D),  with  which  the  shadow  still  moves  in  the  same 
direction  as  the  mirror,  corrects  it  nearly  to  1  D.  The 
myopia  is,  therefore,  9i  D  +  1  D. 

If  with  a  concave  mirror  the  shadow  moves  in  the  con- 
trary direction,  the  patient  either  has  a  myopia  less  than 
1  D  or  he  is  emmetropic  or  hypermetropic.  In  such  a 
case  the  eye  is  corrected  with  successively  stronger  con- 
vex lenses  until  the  shadow  moves  in  the  same  direction 
as  the  mirror.  If  such  a  glass  is  n  D,  the  patient's 
refraction  is  7i  D  —  1  D. 

The  shadow-test  also  has  its  drawbacks.  It  requires 
for  its  success  that  the  pupil  be  widely  dilated — if  neces- 
sary, by  artificial  means.  Even  with  a  w^idely  dilated 
pupil  it  is  not  always  eas}  to  tell  when  the  movement 
of  the  illuminated  field  ceases  c.-  becomes  reversed,  nor 
is  it  always  easy  to  get  the  patient  to  relax  his  accommo- 
dation completely,  as  the  surgeon's  manipulations  excite 
his  attention  and  cause  him  to  fix  some  object  near  him. 
Finally,  the  refraction  obtained,  instead  of  being  that  of 


THE  SHADOW-TEST,   OR  SKIASCOPY.  57 

the  macula,  is  often  only  that  of  a  neighboring  portion  of 
the  eye-ground.  The  method  will  be  found  in  detail 
in  Neustatter's  GnDidrhs  der  Theorie  und  Praxis  der 
Sohattenprobe  (Sl'iafikopie)  nebst  Tafeln  und  Phuntomen 
zur  Skiaskopie,  Miinchen,  J.  F.  Lehmann,  1900.  [For 
American  students  the  most  useful  works  on  the  shadow- 
test  have  been  published  by  Edward  Jackson  and  James 
P.  Thorington.— Ed.] 

[For  the  sake  of  convenience  the  method  of  application  of  the 
shadow-test  in  the  determination  of  repfular  asti,i!:matism  is  inserted. 
Dr.  Jackson's  description  is  given  :  "The  principles  involved  and 
the  methods  to  be  employed  are  essentially  the  same  as  in  myopia 
or  hypermetropia,  but  the  refraction  has  to  be  determined  in  the 
principal  meridians  instead  of  in  any  meridian  indifferently,  as  it 
can  be  where  all  meridians  are  alike.  To  determine  the  refraction 
in  a  certain  meridian  the  light  must  be  made  to  move  back  and 
forth  in  that  particular  meridian  by  rotating  the  mirror  about  an 
axis  at  right  angles  to  it. 

"  The  direction  of  either  of  these  two  principal  meridians  is  re- 
vealed by  the  area  of  light  in  the  pupil  assuming  the  form  of  a 
more  or  less  distinct  band  of  liglit,  extending  across  the  pupil  in 
the  direction  of  this  meridian  when  its  point  of  reversal  is  ap- 
proached. For  the  higher  degrees  of  astigmatism  this  band  is  very 
noticeable,  and  fixes  with  the  greatest  accuracy  the  direction  of  the 
principal  meridian.  When  the  band-like  appearance  is  most  notice- 
able it  is  easy  to  cause  its  apparent  movement  from  side  to  side, 
but  it  is  more  difficult  to  distinguish  the  movement  in  the  direc- 
tion of  the  length  of  the  band.  Still,  this  latter  movement  is  one 
that  is  to  be  especially  watched  and  its  reversal-point  determined. 

"  When  the  amount  of  astigmatism  is  very  low  the  appearance 
of  a  band  may  be  very  indistinct,  or  not  at  all  perceptible;  but  in 
such  cases  it  is  found  that  when  we  have  reached  the  point  of  re- 
versal for  movement  of  the  light  in  one  direction  there  is  still 
distinct  movement,  either  direct  or  inverted,  in  the  direction  at 
right  angles  to  this,  and  we  thus  know  we  have  tested  one  meridian 
of  an  astigmatism,  and  must  in  the  same  way  ascertain  the  point 
of  reversal  for  the  other  at  right  angles  to  it.  When  the  surgeon 
is  closer  to  the  eye  than  the  point  of  reversal  for  either  meridian, 
the  movement  will  be  with  the  light  on  the  ftice  in  all  directions. 
When  he  is  at  the  point  of  reversal  for.the  meridian  which  has  its 
point  nearer  to  the  eye  than  the  other  meridian  there  will  be  no 
distinguishable  movement  in  this  direction,  but  still  a  direct 
movement  at  right  angles  to  it.  When  he  is  between  the  two 
points  of  reversal  there  will,  in  the  direction  of  the  nearer  merid- 
ian, be  an  inverted  movement  of  the  light,  but  in  the  other  merid- 


58  OPHTHALMOSCOPY. 

ian  a  direct  movement.  When  the  farther  point  of  reversal  is 
reached  the  direct  movement  in  its  meridian  ceases,  while  the 
movement  in  the  other  meridian  continues  inverted.  When  the 
surgeon  has  drawn  back  beyond  both  points  of  reversal,  the  move- 
ment is  reversed  in  all  directions. 

''Having  determined  the  amount  of  myopia,  natural  or  artifi- 
cial, in  both  principal  meridians,  the  strength  of  the  cylinder  re- 
quired to  correct  the  astigmatism  will,  of  course,  be  the  difference 
between  the  refraction  for  the  two  meridians.  Having  thus  ascer- 
tained it,  it  is  well  to  put  this  cylinder  before  the  eye  and  to  see 
if  it  does  accurately  correct  the  astigmatism,  giving  the  same 
point  of  reversal  for  all  meridians  of  the  cornea;  and,  for  accu- 
racy, the  spherical  lens  which  will  bring  this  point  of  reversal  to 
the  distance  of  one  or  two  meters  should  be  used  with  it." — Ed.] 


CHOICE  OF  AN   OPHTHALMOSCOPE. 

Before  proceeding  with  a  description  of  ophthalmoscopic 
technic,  it  will  be  well  to  devote  a  few  pages  to  the  dis- 
cussion of  the  instrument  itself.  I  shall  not  attempt, 
however,  to  describe  all  the  ophthalmoscopes  at  present 
in  use,  for  that  alone  would  require  a  book.  Mere  des- 
cription without  criticism  would  be  of  little  practical  value, 
and  to  compare  all  the  various  forms  of  0])hthalmoscopes 
and  test  their  practical  usefulness  would  be  a  Herculean 
task.  I  have,  it  is  true,  used  a  good  many  of  the  best 
and  most  popular  instruments  at  present  in  use,  and  should 
be  in  a  position  to  criticise  them,  but  as  I  am  not  ac- 
quainted with  all  of  them  I  might  be  led  to  do  an  injus- 
tice to  some.  I  shall  permit  myself  to  mention  only  one 
instrument.  It  is  a  small  simple  refraction-ophthalmo- 
scope introduced  by  me  ten  years  ago,  at  least  among  my 
pupils,  in  place  of  Liebreich's  ophthalmoscope,  which,  on 
account  of  its  many  defects,  has  always  been  to  me  a 
thorn  in  the  flesh.  Recently  simpler  ophthalmoscopes  than 
Liebreich's,  for  examining  in  the  inverted  image  only,  have 
been  placed  on  the  market ;  but  in  my  opinion  an  ophthal- 
moscope for  students  should  also  permit  examination  in  the 
erect  image,  or  the  direct  methocf. 

It  will  be  enough  if  I  lay  down  the  principles  on  which 


CHOICE  OF  AN  OPHTHALMOSCOPE.  59 

an  ophthalmoscope  should  be  constructed  to  fulfil  all  the 
requirements.  These  principles  are  the  same  for  all  in- 
struments and,  as  in  the  case  of  the  microscope,  they  are 
extremely  simple.  As  in  the  construction  of  the  latter 
instrument,  the  only  flictors  that  vary  are:  1.  The 
mechanical  portion ;  2.  The  quality  of  the  material  and 
workmanship. 

In  my  experience  most  of  the  larger  instruments  in 
ordinary  use — the  so-called  refraction-ophthalmoscopes — 
in  the  main  show  careful  w^orkmanship,  especially  those 
that  are  turned  out  by  well-known  makers  of  optical 
instruments  in  various  countries.  It  is  always  well,  how- 
ever, to  test  one's  instrument  in  regard  to  the  grinding 
of  the  mirror  and  leases,  the  proper  enumeration  of  the 
lenses,  etc.,  and  to  refuse  it  if  it  is  in  any  way  defective. 
As  regards  the  mechanism,  the  instrument  may  be  con- 
structed according  to  the  views  and  personal  preferences 
of  the  author  or  of  the  purchaser.  The  important  point 
is  that  the  instrument  should  work  properly  and  be  easy 
to  manipulate.  The  proper  construction  in  this  respect 
can  easily  be  deduced  from  what  has  been  said  above  in 
explaining  the  ophthalmoscope.  AVhen  we  come  to  con- 
sider the  mirror  itself,  I  find  from  my  own  experience 
that  it  is  well  to  have  both  a  concave  and  a  plane  mirror, 
or  at  least  a  concave  mirror.  A  plane  mirror  may,  if 
necessary,  be  dispensed  with,  or,  if  the  instrument  does 
not  possess  one,  it  may  be  supplied  by  taking  a  suitable 
piece  from  any  good  mirror  and  scraping  away  the  coat- 
ing from  a  small  spot  in  the  center  if,  for  instance,  it  is 
desired  to  make  a  careful  examination  for  flocculi  in  the 
vitreous,  or  to  employ  the  shadow-test,  although  the 
latter  can  also  be  performed  with  a  concave  mirror. 
The  best  concave  mirror,  in  my  opinion,  is  one  which 
lias  a  focal  distance  of  14  to  17  cm.  This  will  do  equally 
well  for  the  direct  and  for  the  indirect  method.  In  test- 
ing the  focal  distance  of  the  mirror  one  should  notice 
at  the  same  time  whether  the  image  it  reflects  is  sharply 
defined,  as,  for  instance,  a  lamp  placed  at  a  distance,  so 


60  OPHTHALMOSCOPY. 

as  to  determine  whether  the  glass  is  carefully  ground. 
An  important  point  is  the  size  of  the  opening.  It  must 
not  be  too  small  or  it  will  not  admit  enough  light  into 
the  observer's  eye.  This  is  especially  important  in  the 
refraction-ophthalmoscope,  because,  on  account  of  the 
necessity  of  interposing  auxiliary  lenses  and  tilting  the 
mirror,  the  observer  is  often  forced  to  work  at  some  dis- 
tance from  his  patient.  The  diameter  should  be  at  least 
3  mm.  on  the  anterior,  and  a  little  greater  on  the  pos- 
terior surface,  so  that  the  opening  is  slightly  larger  be- 
hind than  in  front.  It  is  particularly  important  that  the 
walls  of  this  short  canal  be  well  blackened.  It  must  not 
produce  any  reflexes  whatever,  because  they  are  exceedingly 
disturbing,  especially  in  examining  in  the  erect  image. 
Even  the  largest  optical  firms  are  not  j)articular  enough  in 
this  respect,  especially  in  the  case  of  cheap  ophthalmoscopes. 
In  all  the  larger  instruments  designed  for  the  measure- 
ment of  refraction,  it  is  absolutely  indispensable  that  the 
mirror  be  capable  of  being  tilted  if  the  measurements  are 
to  be  exact ;  for  if  it  is  desired  to  throw  the  light  from  a 
lamp  placed  to  one  side  of  the  patient  into  the  latter's 
eye,  the  mirror  must  be  turned  slightly  toward  the  lamp, 
as  will  be  seen  in  Fig.  A ;  that  is  to  say,  the  plane  of  the 
mirror  as  seen  from  above  will  form  an  angle  with  the 
plane  of  the  patient's  face.  The  consequence  is  that  the 
observer  looks  obliquely  through  the  lenses  placed  behind 
the  mirror  if  they  are  closely  applied  to  the  mirror ;  but 
if  we  look  obliquely  through  a  spherical  lens,  the  latter 
acts  like  a  cylinder,  that  is,  the  rays  are  refracted  more 
in  one  direction  than  they  would  be  if  they  passed 
through  perpendicularly.  Besides,  if  the  correcting  lens 
is  closely  applied  to  the  mirror,  the  observer  is  farther 
away  from  the  correcting  lens  than  he  should  be.  Hence, 
the  newer  ophthalmoscopes  are  so  arranged  that  the 
mirror  can  be  set  at  an  angle  to  the  plate  which  holds 
the  correcting  lenses,  either  to  one  side  or  the  other,  so 
that  the  lamp  can  be  placed  either  to  the  right  or  to  the 
left  of  the  patient. 


CHOICE  OF  AN  OPHTHALMOSCOPE.  61 

With  the  indirect  method  there  is  no  necessity  of 
tilting  the  mirror,  as  correcting  glasses  are  not,  as  a 
rule,  required.  Hence,  those  instruments  which  are 
provided  with  two  mirrors,  one  for  the  indirect  and  one 
for  the  direct  method,  are  usually  so  arranged  that  only 
the  mirror  for  the  direct  method  can  be  tilted.  But  as 
it  is  sometimes  desirable  to  use  correcting  lenses  in  the 
indirect  method  for  the  purpose,  for  instance,  of  obtain- 
ing an  enlarged  image,  it  is  best,  on  the  whole,  to  have  a 
concave  mirror  of  16  cm.  focal  distance  suitable  for  both 
methods  placed  at  an  angle,  and  to  use  a  small  plane 
mirror  for  the  examination  of  flocculi  in  the  vitreous  and 
for  the  shadow-test.  This  plane  mirror  need  not  neces- 
sarily be  fastened  to  the  ophthalmoscope. 

This  brings  us  to  the  mechanical  portion  of  the  instru- 
ment, and  we  first  have  to  consider  the  most  important 
point,  namely,  the  attachments  for  the  correcting  lenses 
behind  the  opening  in  the  mirror.  The  correcting  lenses 
should  be  as  near  the  mirror  as  possible,  nor  should  too 
many  be  placed  one  above  the  other,  as  that  would  dimin- 
ish the  amount  of  light  in  the  image.  If  one  lens  is 
placed  over  another,  the  two  should  be  in  close  contact, 
so  that  the  observer's  eye  may  be  as  close  as  possible  to 
the  opening  in  the  mirror. 

The  correcting  lenses  are  now  usually  arranged  along 
the  edge  of  a  round  disk,  which  can  be  rotated  behind 
the  mirror  in  such  a  way  that  the  various  lenses  are 
brought  exactly  behind  the  opening  in  the  mirror,  and 
the  center  of  the  lens  always  corresponds  exactly  with 
the  center  of  the  opening.  This  is  accomplished  by 
means  of  catches.  In  many  ophthalmoscopes  two  disks 
of  this  kind  are  placed  one  above  the  other,  so  that  the  ob- 
server always  looks  through  both.  In  others  the  disks  are 
^hanged  according  to  the  lenses  required,  which  is  very 
troublesome.  I  find  that  for  ordinary  j^urposes  I  get 
along  very  well  with  a  single  disk  supplemented  by  a 
quadrant  rotated  on  the  same  axis  and  containing  lenses 
of  very  high  power.     The  quadrant  when  not  in  use  can 


62 


OPHTHALMOSCOPY. 


be  turned  down  toward  the  handle,  as,  for  instance,  in 
the  instrument  designed  by  Loring.  If,  for  example,  the 
disk  contains  1 5  lenses :  Concave  1  to  8  and  convex  1  to 
7,  and  an  empty  hole,  and  the  quadrant  contains  concave 
16  and  convex  16,  and,  in  addition,  concave  32  and  0.5, 


Fig.  G. — Author's  ophthalmoscope. 

the  combination  of  the  disk  and  the  quadrant  places  at 
our  disposal :  Concave  1  to  40  and  convex  1  to  23,  a 
total  of  63  numbers,  and,  in  addition,  the  half  diopters 
from  1  to  8  concave.  If,  instead  of  the  quadrant,  the 
instrument  is  provided  with  an  additional  disk,  the  num- 


CHOICE  OF  AN  OPHTHALMOSCOPE. 


63 


her  of  lenses  at  the  surgeon's  (]isj)osal   is  considerably 
increased. 

As  the  convex  lenses  must  not  be  too  small,  their  num- 


FiG.  H. — Loring's  ophthalmoscope,  with  tilting  mirror,  complete 
disk  of  lenses  from  —  1  to  —  8  and  0  to  +  7,  and  supplemental  quadrant 
containing  ±0.5  and  ±16  D.  This  atibrds  66  glasses  or  combinations 
from  +  23  to  -  24  D. 


ber  in  the  disk  is   necessarily  limited.      The  diameter 
should  not  be  less  than  5  mm. 

Finally,  a  word  in   regard  to  the  convex  lens  used  to 
produce  the  inverted  image.     Much  too  little  attention 


64 


OPHTHALMOSCOPY. 


is  paid  to  this  auxiliary  lens  in  many  ophthalmoscopes. 
As  the  size   of  the  case  is  usually  limited,  it  is  much 


Fig.  I. — Eandall's  modified  Loring  ophthalmoscope,  in  which  the 
"quadrant"  is  moved  by  the  cog  below,  so  that  every  glass  can  be 
brought  to  the  sight-hole  without  removing  the  instrument  from  the  eye. 
A  disk  of  concave  cylinders  0.5  to  4  is  excentrically  mounted,  so  that 
each  can  be  brought  at  any  desired  inclination  of  its  axis  into  combina- 
tion with  any  spherical.  It  gives  51  spherical  lenses  or  combinations. 
The  mirror  can  be  detached  to  substitute  a  weak  light,  plane,  or  more 
concave  mirror,  or  left  off,  uncovering  the  6  mm.  breadth  of  the  lenses 
when  the  instrument  is  used  as  an  optometer. 

better  to  have  one  lens  of  the  proper  size  than  two  small 
ones,  especially  for  the  beginner,  as  it  is  important  that 


CHOICE  OF  AN  OPHTHALMOSCOPE. 


65 


Fig.  J.— Jackson's  ophthalmoscope,  with  two  superposed  slides  of 
fenses  coming  singly  or  combined  behind  the  sight-hole  of  the  tilting 
mirror.  It  gives  35  lenses  or  combinations,  from  +  11  to  — 18  D,  with 
great  convenience,  and  is  exceedingly  simple  and  thin. 

Like  most  other  ophthalmoscopes,  the  figures  are  red  to  indicate 
concave  glasses,  and  white  to  mark  convex,  making  mistake  or  confusion 
as  to  combinations  unlikely. 

Fig.  K. — Marple's  electric  ophthalmoscope. 
5 


66  OPHTHALMOSCOPY, 

the  field  should  be  as  large  as  possible.  For  beginners  it 
is  best  always  to  use  the  same  lens,  which  should  have  a 
strength  of  about  17  D  or  a  focal  distance  of  6  cm. ;  the 
size  of  the  lens  should  not  be  less  than  3.5  cm.  The  best 
size  is  from  3.5  to  4  cm.  The  mounting  of  the  lens  should 
be  sufficiently  wide  to  prevent  its  being  scratched  when 
laid  on  the  table  or  soiled  by  the  fingers  when  in  use.  For 
reasons  which  will  be  given  later  it  is  also  advisable  to 
have  a  short  thick  handle  attached  to  the  rim.  If  other 
convex  lenses  are  needed  in  the  indirect  method  for  the 
purpose  of  obtaining  a  greater  magnification,  a  -fl3  or 
+  14  lens  from  the  lens-case  may  be  called  into  requisition. 
With  a  refraction-ophthalmoscope  the  inverted  image  can 
easily  be  magnified  by  bringing  a  convex  lens  of  2  to  4  D 
behind  the  opening  in  the  mirror  and  at  the  same  time 
coming  closer  to  the  patient. 

The  only  instrument  I  should  advise  anyone  to  buy  is 
one  that  can  be  used  for  the  direct  method ;  that  is,  one 
with  a  considerable  number  of  correcting  lenses  so  at- 
tached that  they  can  be  rapidly  brought  behind  the  open- 
ing in  the  mirror,  as,  for  instance,  by  means  of  the  disk 
just  described.  In  Liebreich's  instrument  the  lenses  are 
placed  in  separate  holders.  This  is  extremely  trouble- 
some and  the  lenses  are  nearly  always  soiled.  It  should 
also  be  possible  to  change  the  number  of  correcting  lenses 
behind  the  mirror  without  removing  the  mirror  from  the 
eye.  For  ordinary  work  a  small  number  of  lenses,  not 
greater  than  twelve,  will  be  found  sufficient.  Hence,  the 
disk  need  not  be  very  great  and  the  price  of  the  instru- 
ment not  unreasonable.  Years  ago  I  had  a  small  oph- 
thalmoscope of  this  kind  made  by  R.  Doerffisl  in  Berlin. 
It  has  a  movable  concave  mirror,  a  disk  with  fourteen 
lenses,  and  the  proper  kind  of  auxiliary  lens.  That  they 
are  strong  is  shown  by  the  fact  that  a  number  of  them 
have  been  bought  and  used  by  my  pupils  in  the  last  ten 
years,  and  the  price  is  so  moderate  (25  marks)  that  one 
feels  justified  in  advising  every  student  to  buy  one  (Fig. 
G).     I  can  also  recommend  it  to  the  practising  physician 


OPHTHALMOSCOPIC  EXAMINATION.  67 

who  does  not  care  to  buy  a  large  or  expensive  instrument, 
as  it  will  be  quite  adequate  to  all  his  needs.  [Among  the 
many 'ophthalmoscopes  at  the  student's  disj)osal,  in  the 
editor's  opinion,  none  is  better  than  the  Loring  oph- 
thalmoscope ;  Jackson's  ophthalmoscope  is  also  excellent. 
Randall's  cylindrical  lenses-attachment  has  been  referred 
to ;  vide  diagrams  H,  I,  and  J. — Ed.] 

THE  METHOD  OF  CONDUCTING  AN  OPHTHALMOSCOPIC 
EXAMINATION. 

The  ophthalmoscopic  examination  is  best  made  in  a 
dark  room  with  a  moderately  large  gas-  or  oil-lamp. 
An  incandescent  light,  on  account  of  the  small  size  of 
the  flame,  cannot  be  used  without  a  special  appliance. 
Ophthalmoscope  lamps  with  electric  lights  are  made  and 
recommended  by  Deus,  Eversbusch,  and  others.  Evers- 
busch's  light  can  also  be  used  for  gas. 

H.  Wolff  has  constructed  an  ophthalmoscope  (obtainable 
from  Doerffel  &  Fiirber,  Berlin,  Friedrichstr,  105a)  which 
is  filled  with  a  small  incandescent  lamp.  The  ophthalmo- 
scopic visual  field  (in  the  erect  image)  is  very  large  with 
this  instrument,  and  at  the  same  time  the  retinal'^eflexes 
are  very  distinctly  seen.  -Similar  electric  ophthalmoscopes 
have  been  constructed  in  England  and  America.  Marple, 
of  New  York,  commends  such  an  instrument  combined 
with  Morton's  well-known  and  excellent  ojihthaluioscope, 
which  can  be  obtained  from  E.  B.  Meyrowitz,  New  York 
and  Paris  (3  Rue  Scribe).  [In  the  opinion  of  the  editor, 
Marple's  electric  ophthalmoscope  (Fig.  K)  is  the  most  use- 
ful instrument  of  this  character  at  present  available.  The 
De  Zeng  instrument  is  also  satisfactory.  Electric  ophthal- 
moscopes are  essential  for  accurate  bedside  work,  and  most 
convenient  on  all  occasions.  They  are  particularly  valu- 
able for  daily  observations  of  the  fundus  after  decompress- 
ing trephining  and  other  operations  conducted  in  the  course 
of  brain  surgery. — Ed.] 

If  an  Auer  incandescent  gas-lamp  is  used,  it  is  to  be 
borne   in    mind    that  the   light   is  more  greenish  white, 


68  OPHTHALMOSCOPY. 

which  gives  the  eye-ground  a  different  color  as  com- 
pared with  the  yellow  light.  The  same  applies  to  ex- 
amination by  daylight,  which  is  allowed  to  enter  the  dark 
room  through  a  suitable  opening,  Avhich,  however,  may  be 
recommended  for  certain  cases  in  which  it  is  important  to 
recognize  the  natural  coloration  of  a  structure  in  the  eye- 
iground.  With  concentrated  daylight  it  is  possible  to 
j recognize  the  much-disputed  yellow  coloration  of  the 
j  macula  lutea  of  the  retina  (Dimmer). 

The  patient  should  be  placed  at  a  table,  at  a  distance 
of  40  to  60  cm.  from  the  observer,  who  sits  opposite, 
with  the  table  on  his  right  hand.  The  table  supports 
the  lamp,  which  should,  if  possible,  be  on  a  level  with 
the  patient's  eye.  The  patient  should  sit  on  a  revolving 
stool,  and  the  lamp  should  be  so  arranged  that  it  can  be 
raised  and  lowered  at  will. 

The  surgeon  should  make  it  a  rule  always  to  examine 
by  lateral  illumination  before  proceeding  with  the  oph- 
thalmoscopic examination  until  the  habit  becomes,  as  it 
were,  second  nature.  This  method  brings  out  many 
changes  that  have  an  important  bearing  on  the  ophthal- 
moscopic examination  and  should,  therefore,  never  be 
neglected.  Tiius,  a  beginner  ipay  waste  a  good  deal  of 
time  in  trying  to  obtain  a  clear  image  of  the  eye-ground 
by  the  direct  method,  because  he  has  neglected  to  exam- 
ine by  lateral  illumination  and  has,  therefore,  failed  to 
discover  opacities  in  the  cornea  or  in  the  lens.  The 
indirect  method  may  be  fairly  successful  even  when  the 
refracting  media  are  somewhat  opaque,  because  the  light 
is  more  intense  and  the  image  is  not  so  greatly  magnified, 
but  not  the  erect  image.  The  surgeon  then  begins  by 
placing  the  lamp  to  his  right  hand,  takes  up  the  convex 
lens  that  accompanies  the  ophthalmoscope,  and  allows  the 
light  (from  the  lamp)  to  pass  through  it,  holding  the  lens 
at  an  angle  and  to  one  side,  so  as  to  throw  a  strong  light 
into  the  anterior  portion  of  the  eye.  By  successively 
directing  the  luminous  apex  of  the  cone  of  light  passing 
through  the  lens  on  the  individual  parts  of  the  eye,  he  ex- 


OPHTHALMOSCOPIC  EXAMINATION.  69 

amines  them  separately,  if  necessary,  with  the  additional 
aid  of  a  good  magnifying  glass.  A  binocular  loupe  such 
as  Berger's  is  exceedingly  useful.  With  it  iris-nodules 
and  other  complex  objects  in  the  anterior  chamber  can  be 
recognized  at  a  glance.     For  a  more  detailed  study  the 

^  larger  loupe  designed  by  Westien  and  particularly  that  of 
Ziess,  which  supplies  electric  illumination  of  the  object  at 
the  same  time,  are  to  be  recommended. 

After  this  inspection  by  lateral  illumination,  the  lamp 
is  placed  by  the  side  of  and  a  little  behind  the  patient, 
so  that  the  light  does  not  fall  directly  into  his  eyes,  but  re- 
mains in  shadow  as  much  as  possible,  and  the  surgeon  pro- 
|ceeds  with  the  ophthalmoscopic  examination.      The  lamp 

X  ■  should  be  as  near  the  patient's  head  as  possible. 

The  second  step  in  the  examination  consists  in  a  simple 
illumination  of  the  eye.  This  exainlaation  bij  transmitted 
lighty  in  which  we  simply  throw  the  light  into  the  patient's 
eye  with  the  concave  mirror  so  that  the  pupil  appears 
red,  reveals,  as  stated  above,  any  opacity  of  the  cornea 
or  of  the  lens  and  vitreous.  In  order  to  see  any  abnor- 
malities near  the  periphery  of  the  lens  or  vitreous,  the 
eye  must  be  examined  in  various  positions,  hence  the 
patient  should  be  told  to  look  up  and  down  and  to  either 
side,  the  surgeon  keeping  the  light  reflex  on  the  pupil  so 
that  it  constantly  appears  red. 

The  third  step  in  the  examination  consists  in  the  em- 
ployment of  the  ■indirect  method j  because  it  affords  a  better 
general  view  of  the  entire  eye-ground.     For  this  purpose 
the  convex  lens  of  17D  is  held  in  front  of  the  patient's 
eye  at  a  distance  of  6  cm.,  corresponding  to  its  focal  dis- 
tance, and  if  the  glass  is  provided  wdth  a  handle,  the  re- 
maining fingers  of  the  hand  that  holds  the  lens  will  not 
^obscure  the  patient's  face  and  interfere  with  the  sight  of 
)the  other  eye.     The  handle,^herefore,  has  a  distinct  ad- 
/ vantage,  because  the  other  eye  must  be  made  to  maintain 
a  certain  direction  by  fixing  an  object  at  a  distance.     Thus, 
while  examining  the  left  eye,  the  patient  is  asked  to  fix 
the  surgeon's  ear,  and  to  do  this  his  right  eye  must  not 


70  OPHTHALMOSCOPY. 

be  covered.  If  the  light  is  now  thrown  into  the  eye 
through  the  lens,  and  the  observer  looks  through  the 
opening  in  the  mirror  and  the  auxiliary  lens,  he  will,  if 
the  auxiliary  lens  and  mirror  are  in  the  proper  position, 
immediately  see  the  optic  nerve  [of  the  left  eye]. 
During  the  examination  the  surgeon  must  accommodate 
for  that  point  between  the  auxiliary  lens  and  the  mirror 
which  corresponds  to  the  position  of  the  image  of  the 
eye-ground,  as  explained  above.  This  is  one  of  the  diffi- 
culties of  this  method.  The  beginner  usually  accommo- 
dates either  for  the  eye  or  for  the  auxiliary  lens  and  gets 
an  imperfect  view  of  the  image,  since  the  latter  is  pro- 
jected between  his  own  eye  and  the  auxiliary  lens. 

To  overcome  this  defect  it  is  advisable  to  practise  with 
the  same  auxiliary  lens  on  reduced  inverted  images  of 
colored  eye-grounds,  such,  for  instance,  as  are  found  in 
the  present  volume.  The  picture  should  be  held  at  a  dis- 
tance of  60  cm.  and  examiued  with  the  auxiliary  lens  of 
17  D  held  at  a  distance  of  about  20  cm.  from  the  picture. 
Incidentally  the  student  will  learn  to  orient  himself  in 
the  inverted  image.  By  practising  in  this  way  he  will 
J  learn  to  know  and  overcome  another  defect  incident  to 
^  the  indirect  method,  namely,  the  reflexes  of  the  auxiliary 
lens.  He  will  soon  learn  to  look  between  them  by  holding 
the  lens  a  little  obliquely.  After  he  has  learned  to  deal 
with  these  reflexes  it  will  be  easier  for  him  to  overcome 
or  disregard  the  corneal  reflex,  which  at  first  is  such  a 
disturbing  factor  in  the  examination. 

As  soon  as  he  has  mastered  the  art  of  obtaining  the 
inverted  image  in  the  actual  subject,  he  must  learn  to 
keep  the  patient's  other  eye  under  observation  by  indirect 
vision,  so  as  to  control  its  direction.  Children  often  dis- 
obey the  order  to  look  in  a  certain  direction.  Thus,  they 
often  will  not  look  at  the  surgeon's  left  ear,  when  he 
wishes  to  inspect  the  left  optic  nerve,  etc.  To  avoid 
wasting  time,  the  surgeon  must  insist  that  the  patient 
keep  his  eye  in  the  same  direction  for  some  time.  But 
after  asking  the  patient  to  fix  his  left  ear,  the  surgeon 


OPHTHALMOSCOPIC  EXAMINATION,  71 

must  be  careful  not  to  make  it  impossible  by  covering  the 
patient's  right  eye  with  the  hand  that  holds  the  auxiliary 
lens,  as  has  been  explained  above.  He  must  rest  his  hand 
on  the  patient's  face  in  such  a  way  as  not  to  obstruct  the 
other  eye  and  make  it  difficult  for  the  patient  to  fix  the 
object  he  is  asked  to  look  at.  If  the  auxiliary  lens  is 
supplied  with  a  handle  (as  in  the  lens  which  goes  with 
Haab's  ophthalmoscope)  it  is  very  much  easier  to  manip- 
ulate. 

The  surgeon  must  further  learn  to  raise  the  upper  eye- 
lid with  one  of  the  fingers  of  the  hand  that  holds  the 
convex  lens.  This  may  be  necessary  in  examining  the 
eye-ground  while  the  patient  is  looking  down,  or  in  exam- 
ining patients  lying  in  bed.  It  is  best  done  by  laying 
the  ulnar  side  of  the  tip  of  the  fourth  finger  lightly  against 
the  upper  lid  and  drawing  it  upward.  The  surgeon  should 
never  be  content  with  an  examination  of  the  optic  nerve 
and  its  immediate  neighborhood,  but  should  train  himself 
to  inspect  the  peripheral  portions  of  the  eye-ground  as 
well,  and  for  this  purpose  should  ask  the  patient  to  look 
up  and  down  and  to  either  side. 

To  obtain  a  view  of  the  optic  nerve  of  the  right  eye  the 
patient  is  asked  to  look  past  the  surgeon's  right  ear  at  the 
wall,  as  the  optic  nerve  lies  about  15  degrees  to  the  nasal 
side  of  the  posterior  pole  of  the  eye.  This,  the  most 
difficult  part  of  the  examination,  is  extremely  important, 
because  it  shows  the  most  important  part  of  the  retina. 
As  the  corneal  reflex  is  a  very  disturbing  factor  and 
the  pupil  contracts  because  the  rays  of  light  enter  perpen- 
dicularly, the  image  is  weakly  illuminated  and  it  requires 
^reat  practise  to  see  this  part  of  the  eye-ground  clearly. 
^  The  best  plan  is  to  ask  the  patient  to  look  into  the 
observer's  left  eye  when  it  is  desired  to  examine  his  left 
macula  lutea.  The  surgeon  then  tries  to  get  the  image  of 
the  left  optic  nerve  into  the  temporal  portion  of  the  con- 
vex lens,  and  turns  the  mirror  very  slightly  toward  the 
nose,  whereupon  the  macula  lutea  becomes  visible  in  the 
nasal  portion  of  the  lens   and  the   troublesome  corneal 


72  OPHTHALMOSCOPY. 

reflex  disappears  toward  the  temple.  To  examine  the 
right  macular  region  the  patient  is  asked  to  look  at  the 
observer's  right  ear  and  the  same  steps  are  again  repeated. 
Care  must  be  taken  not  to  allow  any  light  to  fall  into  the 
other  eye,  so  as  to  avoid  any  contraction  of  the  pupil, 
and  if  the  pupil  is  too  small  in  spite  of  this  precaution 
it  must  be  dilated. 

It  is  of  the  greatest  importance  in  using  this  method 
that  the  auxiliary  lens  be  absolutely  clean  and  free  from 
scratches.  Impurities  in  the  glass  always  attract  the  be- 
ginner's eye  and  thereby  make  it  difficult  for  him  to  see 
the  eye-ground ;  and,  besides,  there  is  danger  that  they 
may  be  mistaken  for  abnormalities  in  the  eye-ground  itself, 
so  that  things  seem  to  be  seen  there  which  in  reality  do 
not  exist.  The  most  minute  spots,  such  as  the  finger 
usually  leaves  on  the  glass,  appear  white  in  the  eye- 
ground  and  closely  simulate  white  spots  in  the  retina, 
for  example,  such  as  are  found  in  albuminuria  and  diabetes. 

After  the  eye-ground  has  been  sufficiently  studied  by 
the  indirect  method,  the  surgeon  proceeds  to  the  fourth 
step  :  examination  by  the  direct  method.  To  do  this  most 
successfully,  the  lamp  should  be  placed  close  to  that  side 
of  the  patient's  head  which  corresponds  to  the  eye  to  be 
examined.  The  beginner  will  do  well  to  confine  himself 
to  the  patient's  right  eye,  which  he  can  inspect  with  his 
own  right  eye,  as  most  people  find  this  the  easier  of  the 
two.  After  placing  the  patient  so  that  the  lamp  is  on  his 
right  side,  the  surgeon  simply  throws  the  light  into  the 
eye.  Then,  still  keeping  the  light  in  the  eye,  he  gradu- 
ally comes  nearer  and  nearer,  and  finally  as  near  as  pos- 
sible, until  he  begins  to  see  in  the  red  glare  of  the  pupil 
details  such  as  portions  of  blood-vessels  in  the  eye-ground, 
taking  good  care,  as  explained  above,  to  relax  his  accom- 
jmodation.  The  observer  should  always  imagine  that  he 
'  is  looking  through  the  patient's  head  into  infinity.  If  the 
patient  has  been  told  to  look  straight  ahead  and  to  the 
left  (into  infinity),  the  surgeon  will  soon  get  a  view  of  the 
optic  nerve  by  tracing  one  of  the  retinal  vessels  back  to 


OPHTHALMOSCOPIC  EXAMINATION.  73 

it.  The  exaaiination  of  the  left  eye  is  somewhat  more 
difficult,  because  it  must  either  be  examined  with  the  left 
eye  to  avoid  collision  between  the  observer's  and  the  pa- 
tient's nose,  or  the  patient  must  turn  his  head  away  from 
the  light.  On  the  whole,  it  is  best  to  learn  from  the  be- 
ginning to  use  the  right  eye  in  examining  the  patient's 
right  eye,  and  the  left  eye  to  examine  the  patient's  left 
eye. 

In  looking  for  the  erect  image  it  is  well  to  observe  the 
following  points  :  If  the  light  is  thrown  on  the  patient's 
face  by  means  of  a  concave  mirror  held  at  a  distance  of  5 
cm.,^  and  the  observer  looks  through  the  opening  in  the 
mirror,  he  will  see  at  the  center  of  the  brightly  illuminated 
field,  which  has  the  same  shape  as  the  mirror,  a  dark, 
blurred  spot  which  represents  the  image  of  the  opening. 
This  can  be  most  easily  studied  by  throwing  the  light  on  the 
patient's  forehead.  It  will  be  noted  that  the  pupil  appears 
red  as  soon  as  this  image  of  the  opening  is  brought  to  co- 
incide with  it,  hence  if,  without  accommodating,  we  con- 
trol the  position  of  this  dark  spot  as  we  approach  the  eye 
(when  the  spot  becomes  more  distinct),  and  by  means  of 
indirect  vision  keep  this  dark  spot  constantly  on  the  pa- 
tient's pupil,  the  latter  will  constantly  appear  red,  and 
some  portion  of  the  eye-ground  will  become  visible  as  soon 
as  the  proper  point  has  been  reached  and  the  refracting 
media  permit  of  the  production  of  a  distinct  image. 
Hence  it  is  not  enough  in  the  direct  method  simply  to 
direct  the  light  from  the  mirror  into  the  patient's  eye, 
but  the  center  of  the  mirror,  or,  in  other  words,  the  o])en- 
ing  must  be  made  to  coincide  with  the  j)atient's  jHipil, 
because  this  is  the  only  way  in  which  the  rays  leaving  the 
patient's  eye  can  enter  the  observer's  eye. 
,  If  correcting  lenses  are  necessary  it  is  better  to  insert 
them  without  removing  the  mirror  from  the  eye,  that  is, 
by  simply  turning  the  disk  of  lenses.  By  doing  this  the 
observer  will  learn  to  keej)  his  accommodation  relaxed. 

It  is  a  very  good  plan  to  begin  one's  studies  in  ophthal- 
^  AVilli  a  i)liine  minor  6  to  10  cm. 


74  OPHTHALMOSCOPY. 

moscopy  on  the  rabbit,  and  I  have,  therefore,  given  an 
illustration  of  the  rabbit's  optic  nerve  and  surroundings 
in  this  book  (Fig.  Q,  a).  The  rabbit's  pupil  is  naturally 
large,  and  the  eye  is  usually  at  rest ;  besides,  the  eye  is 
hypermetropic,  and  the  emerging  rays  therefore  diverge, 
making  it  easier  to  obtain  a  direct  image. 

Should  we  use  the  plane  or  the  concave  mirror  in  the 
direct  method?  I  should  answer  this  question  by  saying 
that  both  the  plane  and  the  concave  mirrors  have  their 
advantages.  But  the  examiner  should  make  himself  per- 
fectly familiar  with  the  color-gradations  in  the  eye-ground, 
especially  the  optic  nerve,  with  at  least  one  of  them.  I 
cannot  say  that  abnormal  colors,  such  as  pallor  of  the 
optic  nerve  or  gray  discoloration,  can  be  seen  better  with 
the  plane  than  with  a  good  concave  mirror,  but  if  two 
mirrors  are  used,  the  question  is  complicated  by  the  fact 
that  it  becomes  necessary  to  train  one's  self  to  recoguize 
a  special  set  of  abnormal  colorings  for  each  mirror. 
Hence  if  the  student  uses  only  one  mirror,  he  will  obtain 
a  certain  proficiency  in  diagnosis  earlier.  In  any  event, 
it  is  best  always  to  use  the  same  mirror  for  the  direct 
method.  I  have  no  doubt,  however,  that  the  examination 
of  the  macula  will  be  more  exact  if  a  concave  mirror  is 
used.  A  concave  mirror  brings  out  the  macula  itself  and 
any  alterations  that  may  be  present  better  than  does  the 
plane  mirror,  for  the  simple  reason  that  in  examining  this 
portion  of  the  eye-ground  the  pupil  is  contracted,  and, 
owing  to  the  darker  pigmentation  of  the  macular  region, 
the  image  is  dark  enough  even  with  the  concave  mirror, 
and  altogether  too  dark  and  indistinct  if  a  plane  mirror 
is  used. 

THE  NORMAL  EYE=GROUND. 

The  appearances  of  the  normal  eye-ground  as  seen 
with  the  oplithalmoscope  present,  as  I  have  stated  in  the 
beginning,  so  many  variations  that  a  thorough  knowledge 
of  the  normal  conditions  is  of  the  greatest  importance 
before  proceeding  to  a  study  of  the  pathologic  alterations. 


THE  NORMAL  EYE-GROUND.  75 

/  cannot  too  strongly  advise  the  beginner  to  study  normal 
eyes  as  often  and  as  thoroughly  as  possible. 

But  an  accurate  knowledge  of  the  anatomic  structure 
of  the  various  parts  is  equally  necessary  for  a  proper 
uuderstanding  of  the  normal  conditions  in  the  eye-ground. 
These  are  explained  in  Figs.  2,  3,  and  14. 

The  first  thing  we  notice  on  looking  into  the  eye- 
ground  is  the  peculiar  red  coloration,  which  is  very  often 
misinterpreted  and  described  as  "abnormal  redness."  It 
is  due  to  the  fact  that  the  choroid,  as  its  name  implies, 
possesses  a  great  number  of  blood-vessels,  especially  in 
the  anterior  layer  next  to  the  retina — viz.,  the  plexus  of 
the  choriocapillaris — which  becomes  more  and  more  dense 
as  we  approach  the  posterior  pole.  The  red  color  of  the 
blood  in  these  vessels  is  chiefly  responsible  for  the  red 
color  of  the  eye-ground.  It  is  partly  due  also  to  the  color 
of  the  retinal  vessels,  although  they  play  a  very  insignifi- 
cant part.  The  purple  color  of  the  optic  nerve  has  very 
little  to  do  with  it.  We  cannot  see  it  as  such  any  more  than 
we  can  appreciate  a  delicate  rose  tint  on  a  deep  red  color, 
not  to  mention  the  fact  that  the  purple  color  of  the  optic 
nerve  is  very  faint  or  disappears  altogether  under  illu- 
mination. 

But  the  color  of  the  eye-gi'ound  varies  considerably  in 
intensity.  In  some  individuals  it  appears  a  light  yellow- 
ish-red, in  others  the  color  varies  from  a  dark  red  to  a 
brownish-red.  This  variation  is  due  to  the  variable 
amount  of  pigment  contained  in  the  eyes.  Brunettes,  as 
a  rule,  have  darker  eyes  than  blondes.  The  pigment 
may  be  variously  distributed.  The  more  intense  the  pig- 
mentation of  the  retinal  pigment-epithelium,  the  more 
uniform  will  be  the  dark  red  color  of  the  eye-ground, 
because  the  red  color  of  the  choroid  is  more  or  less  ob- 
scifred  and  the  choroidal  vessels  cannot  be  seen.  In 
other  individuals  the  pigment  may  be  chiefly  in  the 
choroid,  especially  between  the  vessels,  the  epithelium 
of  the  retina  being  sparingly  supplied  with  pigment. 
Again,  the  choroidal  vessels  do  not  always  stand  out  with 


76  OPHTHALMOSCOPY. 


* 


equal  distinctDess  behind  the  retinal  vessels.  In  some 
cases  we  only  see  dark  areas  which,  on  closer  examina- 
tion, turn  out  to  be  pigmented  "  intervascular  spaces  of 
the  choroid''  (Figs.  1,  6,  a,  d,  a,  22,  etc.).  In  other  cases 
the  entire  plexus  of  retinal  vessels  reveals  itself  at  once 
(Fig.  5,  6),  owing  to  the  presence  of  pigment  between  the 
vessels.  If  there  is  an  entire  absence  of  pigment  in  the 
retina  and  choroid,  as  in  the  albino,  the  vessels  of  the 
choroid  appear  red  on  a  white  ground  (Fig.  10,  6).  The 
latter  corresponds  with  the  sclera.  In  individuals  who, 
without  being  absolute  albinos,  possess  very  little  pig- 
ment, as  blondes,  for  instance,  the  choroidal  vessels  are 
occasionally  seen  as  red  lines  on  a  light  red  ground 
(Fig.  4). 

In  regard  to  the  pigmentation  of  the  background,  it  is 
to  be  remembered  that  the  region  about  the  posterior  pole 
corresponding  to  the  macula  and  the  neighborhood  of  the 
optic  nerve  is  usually  darker  than  the  peripheral  portions 
(see  Fig.  1  and  many  of  the  other  pictures). 

The  dark  brownish-red  spot  in  the  middle  of  the  macula 
is  due  chiefly  to  the  thinning  of  the  retina  at  that  point  (see 
Fig.  14).  As  a  result  the  pigment  of  the  pigment  epithe- 
lium and  of  the  clioroid  is  seen  more  distinctly  through  the 
attenuated  membrane.  The  choroidal  pigmentation  is 
deepest  where  the  choroid  joins  the  optic  nerve ;  and  at 
this  point  we  sometimes  see  more  or  less  distinctly  a 
black  ring,  the  so-called  choroidal  ring  (Figs.  1  and  5, 
etc.).  Sometimes  there  is  a  clear  space  between  the  optic 
nerve  and  the  choroidal  border,  forming  a  more  or  less 
complete  white  ring,  owing  to  the  sclera  appearing  be- 
tween the  nerve-substance  and  the  choroidal  border. 
Hence  this  white  ring  is  known  as  the  scleral  ring  (Figs. 
1  and  5,  etc.).  The  substance  of  the  optic  nerve  in  the 
ophthalmoscopic  image  appears  grayish-red  and  partly 
transparent,  the  nasal  portion  being  somewhat  darker 
than  the  temporal,  owing  to  the  greater  aggregation  of 
nerve-fibers  emerging  in  the  nasal  portion.  The  center 
is  frequently,  but  not  always,  the  lightest.     This  depends 


THE  NORMAL  EYE-GROUND.  77 

on  the  presence  or  absence  of  a  more  or  less  developed  ex- 
cavation in  the  center  (Fig.  2,  a).  The  deeper  this  excava- 
tion, the  more  apparent  the  white  lamina  cribrosa  in  the 
center,  and  the  brighter,  therefore,  the  corresponding  area. 
The  optic  nerve  of  the  rabbit  has  a  very  distinct  excavation 
(Fig.  6,  a).  It  shows  very  plainly  the  manner  in  which 
the  vessels  distribute  themselves  over  the  retina  without 
emerging  from  the  funnel-shaped  excavation.  AVhen  the 
excavation  is  very  deep,  so  that  the  lamina  cribrosa  is 
plainly  seen  at  the  bottom,  it  is  called  a  jAysiologic  ex- 
cnvatlon  (see  Figs.  5,  h^  54,  b).  The  lamina  cribrosa  is  ^_ 
recognized  as  a  collection  of  gray  dots  on  the  floor  of  the  ^ 
excavation.  The  border  is  formed  by  a  delicate  rim  trav- 
ersed by  the  vessels  as  they  dip  down  into  the  excavation. 

The  optiG  nerve  is  not  always  circular  in  outline ;  it 
may  be  normally  somewhat  oval  in  either  direction. 
Under  normal  conditions  it  does  not  project  beyond  the 
retina,  or  if  it  does,  only  to  a  very  slight  extent  in  the 
nasal  third,  hence  it  is  very  much  better  to  use  the  term 
optic  dlsky  rather  than  to  describe  it  as  a  papilla. 

The  retina  being  transparent,  except  where  it  is  covered 
by  pigment-epithelium,  is  almost  invisible  in  the  ophthal- 
moscopic image.  Occasionally  a  delicate  striation  of  nerve- 
fibers  is  visible  about  the  optic  nerve,  especially  above 
and  below  it.  In  youthful  individuals  with  darkly  pig- 
mented eye-grounds  it  is  usually  possible  to  see  moderately 
well-marked  reflexes  on  the  anterior  surface  of  the  retina 
about  i\\Q  fovea  centralis  and  the  optic  nerve.  They  appear 
as  grayish-white,  irregular  spots  among  the  vessels,  or  as 
bright  lines  along  the  vessels,  and  very  often,  even  in  later 
years,  as  a  ring  about  the  fovea  centralis  (see  Fig.  5,  a), 
or  a  small  ring,  or  small  bright  sickle  at  the  center  of  the 
fovea. 

AVe  recognize  these  bright  spots  as  reflexes  by  their 
peculiar  sheen  and  by  the  fact  that  their  shape  and  posi- 
tion are  affected  by  the  movements  of  the  mirror.  They 
are  most  marked  when  the  indirect  method  is  used,  es- 
pecially if  the  pupil  is  not  well  dilated. 


78  OPHTHALMOSCOPY. 

The  strongest  of  these  reflexes  is  seen  about  the  fovea 
centralis,  and  unless  the  observer  looks  directly  on  the 
macula  he  will  only  see  a  semilunar  portion  of  it,  usually 
the  nasal  half  first.  If  the  entire  reflex  is  seen  at  once, 
it  usually  appears  as  an  oval  with  its  long  diameter  in  the 
transverse  direction  and  its  vertical  diameter  correspond- 
ing approximately  with  that  of  the  optic  nerve,  while  the 
margin  of  the  oval  is  sharply  defined  toward  the  center 
of  the  fovea  and  gradually  disappears  toward  the  periph- 
ery. Occasionally  this  reflex  appears  circular.  The 
oval  form  cannot,  as  stated  by  Johnson,  be  due  to  the 
fact  that  the  fovea  centralis  itself  in  most  cases  has  a 
slightly  oval  shape,  for,  as  I  have  frequently  observed,  the 
shape  of  the  oval  in  any  case  of  well-marked  oval  reflex  is 
not  affected  by  placing  the  lamp  above  the  patient's  head. 
AVithin  the  macular  reflex  the  eye-ground  is  usually 
very  dark,  the  coloring  being  deepest  at  the  center  where 
there  are  no  reflexes,  with  the  exception  of  a  minute  point 
at  the  center  surrounded  by  a  dark  foveal  spot  (see  Figs.  1 
and  5,  a). 

The  macula  can  be  examined  only  by  means  of  the 
direct  method,  which  gives  a  magnified  image.  By  this 
method  it  is  seen  that  the  central  reflex  point  is  formed 
by  a  small  shining  sickle,  which  moves  about  the  center 
of  the  fovea  as  the  observer  moves  his  head,  in  such  a 
way  that  the  points  of  the  sickle  are  always  directed  to- 
ward him.  If  the  observer  looks  into  the  eye  along  the 
nasal  border  of  the  corneal  reflex,  the  points  of  the  sickle 
will  be  directed  toward  the  temporal  side,  and  if  he  looks 
along  the  temporal  border  of  the  corneal  reflex,  the  points 
of  the  sickle  will  be  directed  toward  the  nasal  side,  etc. 
If  the  observer  can  succeed  in  looking  directly  into  the 
eye  along  the  foveal  axis,  that  is  to  say,  as  much  as  pos- 
sible through  the  corneal  reflex,  the  sickle  will  change  to 
a  small  ring  about  equal  in  size  to  the  largest  venous  trunk 
of  the  optic  disk.  The  bright  semitransparent  corneal 
reflex  is  very  disturbing  in  this  examination,  because  it  lies 
immediately  in  front  of  the  central  portion  of  the  macula. 


THE  NORMAL  EYE-GROUND.  79 

If  the  pigmentation  is  only  moderate,  we  see  in  the 
region  of  the  macula  liitea,  especially  near  its  center,  in 
the  region  of  the  somewhat  darker  foveal  spot,  a  delicate 
stippling  of  the  eye-ground ,  giving  the  appearance  of  a 
mosaic  composed  of  minute  light  and  dark  spots.  This 
stippling  simply  represents  the  irregular  pigmentation  of 
the  pigment-epithelium  of  the  retina.  It  may  be  more 
or  less  visible  in  the  entire  eye-ground  if  the  pigmentation 
is  not  very  marked. 

Dimmer,^  who  studied  the  reflexes  on  the  anterior  sur- 
face of  the  retina  with  great  care,  has  pointed  out  that 
the  smaller  foveal  reflex  is  due  to  the  regular  reflection 
of  the  light  at  the  central,  that  is  the  deepest,  portion  of 
the  retinal  pit,  and  represents  an  inverted  image  of  the 
sickle-shaped  or  circular  portion  of  the  mirror  which  lies 
nearest  the  opening.  For  the  center  of  the  retinal  pit 
forms  a  small  concave  mirror  (see  Fig.  14,  a-e)  which  re- 
flects the  light  in  such  a  way  that  it  can  emerge  from  the 
pupil  under  examination.  But  the  rays  that  are  reflected 
from  the  edge  of  the  retinal  pit  (that  is  to  say,  periphe- 
rally from  the  foveal  reflex)  cannot  leave  the  pupil,  hence 
we  usually  see  no  reflexes  in  the  remaining  portion  of  the 
pit,  which  accordingly  appears  dim.  Occasionally  we  see 
an  additional,  somewhat  larger,  luminous  ring,  concentric 
with  the  foveal  reflex.  Beyond  the  border  of  the  pit  the 
rays  of  light  are  again  reflected  in  such  a  way  that  they  can 
leave  the  pupil,  hence  the  bright  reflex  of  the  macular  ring 
which  has  been  mentioned.  The  sharp  central  border 
of  this  oval,  therefore,  corresponds  to  the  point  where  the 
retina  begins  to  become  thinner  to  form  the  pit;  or  in 
other  words,  to  the  sides  of  the  pit.  It  follows  that  the 
macular  reflex  exactly  corresponds  with  the  outline  of  the 
central  retinal  pit,  and  can  therefore  be  utilized  to  de- 
termine the  size  of  the  latter.  Since  the  optic  disk  has  an 
average  diameter  of  1.5  mm.,  the  vertical  diameter  of 
the  fovea  is  approximately  the  same,  while  the  horizontal 
is  somewhat  greater,  disregarding  individual   variations 

^  Dimmer,  Die  Ophthalmoscopischen  Lichtrejlexe  der  Netzhaut,  1891. 


80  OPHTHALMOSCOPY. 

that  occur  here  as  well  as  in  the  diameter  of  the  optic 
nerve.  With  the  direct  method  and  an  ordinary  con- 
cave mirror,  the  large  foveal  reflex  (marginal  reflex) 
appears  very  faintly  or  not  at  all,  owing  to  the  small 
amonnt  of  light  illuminating  the  eye-ground  in  this 
method.  It  appears  a  little  more  distinctly  if  a  strong 
concave  mirror — one  of  8  cm.  focal  distance,  for  instance — 
is  used. 

The  other  reflexes  of  the  retina,  especially  those  that 
follow  the  course  of  the  vessels  (see  Fig.  5,  a),  are  formed 
very  much  in  the  same  way  as  the  macular  reflex.  Ac- 
cording to  Dimmer's  investigations  (loc.  cit.)  they  are  pro- 
duced by  concave  cylindrical  or  spheroconcave  surfaces 
found  on  the  inner  surface  of  the  retina.  These  surfaces 
project  at  a  certain  distance  inverted  images  of  those  por- 
tions of  the  ophthalmoscope  from  which  the  light  reaches 
them . 

In  the  region  of  the  retina  our  attention  is  next 
arrested  by  the  blood-vessels.  The  first  point  that  we 
notice  is  that  they  all  meet  on  the  optic  disk,  as  the 
retina  receives  its  entire  blood-supply  from  the  arteria 
centralis  i^etince  which,  with  the  vena  centralis  retinocy 
occupies  the  axis  of  the  optic  nerve  at  its  entrance  into 
the  globe.  Both  the  artery  and  the  vein  break  up  into 
their  branches  either  on  the  optic  disk  or  (sometimes) 
before  they  reach  it.  The  arteries  are  recognized  in  the 
ophthalmoscopic  image  by  the  fact  that  they  have  a 
lighter  color  and  a  little  brighter  and  broader  central 
stripe  than  the  veins.  These  diflerences  in  color  can 
only  be  seen,  however,  in  the  coarser  branches,  just  as 
the  reflexes  appear  much  more  plainly  in  the  thicker 
vessels  and  in  the  stronger  magnification  of  the  direct 
method.  The  bright  stripe  along  the  center  of  the  vessel, 
according  to  Dimmer  (loc.  cit.),  is  due  in  the  case  of  the 
arteries  to  the  reflection  of  the  light  by  the  blood-cor- 
puscles in  the  axial  stream,  and  in  the  case  of  the  veins 
to  a  similar  reflection  by  the  anterior  surface  of  the  blood- 
column.     Hence  the  middle  stripe  in  the  arteries  is  red- 


THE  NORMAL  EYE-GROUND.  81 

dish,  while  that  in  the  veins,  being  a  simple  reflex,  is 
white.^ 

The  course  of  the  arteries  is,  on  the  whole,  straighter 
than  that  of  the  veins.  The  central  artery,  like  the 
central  vein,  subdivides  into  a  variable  number  of 
branches  in  the  last  segment  of  the  optic  nerve,  or  in 
the  excavation,  or  upon  the  optic  disk.  The  two  prin- 
cipal branches  in  both  systems  run  at  first  up  and  down  ; 
soon  they  subdivide  again,  so  that  we  can  make  out  an 
inferior  and  a  superior  temporal  artery  and  vein.  In  some 
cases  we  can  also  distinguish  a  nasal  artery  and  vein 
carrying  the  blood  to  and  away  from  the  nasal  portion. 
The  important  region  of  the  macula  is  supplied  in  part 
by  vessels  coming  directly  from  the  optic  nerve  and  in 
part  by  branches  of  the  inferior  and  superior  temporal 
artery  and  vein  which  arch  around  the  macula.  Hence 
we  usually  see  in  the  macula  and  its  immediate  surround- 
ings only  delicate  vessels  radiating  more  or  less  toward 
the  center,  although  it  is  impossible  to  trace  them  to  the 
center  of  the  fovea,  even  in  the  direct  method.  They 
usually  disappear  from  sight  near  the  inner  border  of  the 
macular  reflex.  That  they  do  reach  the  center  of  the 
fovea,  however,  is  shown  by  the  well-known  entoptic 
arterial  figure  elicited  by  moving  a  small  opening  to 
and  fro  in  front  of  the  eye,  or  by  moving  a  candle  from 
side  to  side  in  the  dark. 

In  the  peripheral  portions  of  the  retina  the  vessels  are 
few  in  number,  of  minute  caliber,  and  mostly  radiate 
toward  the  periphery.  The  arrangement  of  the  vessels 
is  atypical  in  the  following  cases  : 

(1)  When  there  is  a  so-called  cilioretlnal  irssel.  In 
that  case  a  delicate  artery  appears  at  the  temporal  border 
of  the  optic  disk.  It  arises  in  the  choroid,  passes  into 
tjie  region  of  the  opticus,  enters  the  retina,  and  there 

^  In  the  pictures  of  this  volume  it  has  been,  for  technical  reasons,  im- 
possible to  reproduce  these  vascular  reflexes  accui-ately,  espt'cially  in 
regard  to  width  and  color,  not  to  mention  the  fact  that  with  the  slight 
magnification  of  the  indirect  method  the  reflexes  are  at  best  very  indis- 
tinct. 

6 


82  OPHTHALMOSCOPY. 

pursues  a  general  direction  toward  the  macula.  This 
condition  is  not  very  rare  and,  when  present,  is  usually 
found  in  both  eyes. 

(2)  When  there  is  an  opticociliary  vessel.  This  is  ranch 
rarer.  It  is  a  branch  of  the  central  vein  or  central  artery 
and  does  not  run  as  far  as  the  retina,  disappearing  at  the 
border  of  the  optic  disk.  In  other  words,  it  does  not 
reach  the  vascular  plexus  of  the  choroid. 

(3)  Instead  of  the  venous  blood  from  the  choroid  being 
carried  off  by  the  vortex-veins  in  the  equatorial  region 
(Fig.  10,  6),  we  often  see,  in  highly  myopic  eyes,  poste- 
rior vortex-veins  which  have  a  similar,  but  less  extensive 
ramification  and  carry  off  the  choroidal  blood  at  the  edge 
of  the  optic  disk  (Fig.  45,  a).  Why  these  posterior  vor- 
tex-veins should  be  found  so  often  in  highly  myopic  eyes 
I  cannot  as  yet  understand. 

Pulsation  Phenomena. 

The  pulse-phenomena  seen  in  the  eye-ground  call  for  a 
careful  description.  When  we  look  at  the  richly  branch- 
ing vessels  of  the  eye-ground  for  the  first  time,  we  cannot 
help  asking  ourselves  why  they  lie  so  rigid  and  immovable 
and  give  no  sign  of  pulsation,  unless  it  be  an  occasional 
beat  at  one  or  more  of  the  extreuiities  of  the  veins  on  the 
optic  disk.  The  reason  why  we  usually  cannot  see  any 
distinct  pulsation  in  the  arteries  of  the  retina,  or  only  a 
very  slight  pulsation,  is,  in  the  first  place,  the  fact  that 
vessels  of  such  minute  size  show  little  or  no  pulsation 
because  the  pulse-wave  has  become  too  weak  by  the  time 
it  reaches  a  small  artery.  It  must  never  be  forgotten 
that  we  see  the  eye-ground  greatly  magnified  with  the 
ophthalmoscope,  and  that  if  we  examine  the  globe  Avith 
the  naked  eye,  the  retinal  arteries  even  where  they  are 
widest,  that  is,  on  the  papilla,  appear  only  as  delicate  red 
lines. 

Another  reason  commonly  given  for  the  absence  of 
pulsation  in  the  retinal  arteries  is  the  intraocular  pressure 
which  counteracts  the  pulse-wave. 


THE  NORMAL  EYE-GROUND.  83 

It  is,  however,  possible,  with  great  care,  to  see  true 
pulsating  movements  in  the  retinal  arteries  of  normal 
individuals,  but  only  where  the  course  of  the  artery  is 
curved. 

After  a  series  of  careful  examinations  I  have  reached 
the  conclusion  that  if  one  of  the  larger  retinal  arteries 
in  the  region  of  the  papilla  is  distinctly  curved  we  can 
always  see  a  movement  of  pulsation,  manifesting  itself 
as  a  bulging  of  the  arch  with  the  systole  or  as  a  slight 
to-and-fro  movement  at  the  center  in  a  direction  perpen- 
dicular to  the  chord  of  the  arc.  If  there  are  two  curves 
in  succession,  forming  a  letter  S,  the  phenomenon  is  even 
more  distinct.  It  is  also  brought  out  more  clearly  by 
vigorous  heart-action.  This  pulsatory  locomotion  is  more 
easily  and  more  frequently  seen  than  is  the  pulsatory  vari- 
ation in  caliber,  or,  in  other  words,  the  alternate  expan- 
sion and  contraction  of  the  blood-vessels.  The  latter 
phenomenon  may  be  seen  in  heart  cases.  Another  form 
of  locomotion — a  pulsatory  backward  and  forward  move- 
ment of  bifurcations  in  the  larger  arterial  branches — is 
also  seen  in  cases  of  heart-disease. 

On  the  other  hand,  there  is  a  kind  of  artificial  pul- 
satory movement,  best  described  as  an  intermittent  influx, 
which  can  be  produced  in  any  normal  eye.  If,  while 
carefully  looking  at  the  papilla,  a  gradually  increasing 
pressure  is  exerted  with  the  finger  [on  the  eye  under 
examination]  we  can  see  the  to-and-fro  pulsation  of  the 
blood-column  in  the  ends  of  the  arteries  on  the  papilla. 
This  phenomenon  can  be  observed  even  by  the  indirect 
method,  but,  like  all  pulse-phenomena  in  the  eye-ground, 
appears  more  distinctly  when  the  direct  method  is  used. 
By  the  latter  we  also  see  how  the  intermitting  influx  is 
produced.  As  soon  as  the  pressure  of  the  finger  reaches 
a  certain  degree,  the  ends  of  the  arteries  on  the  papilla 
are  emptied,  and  at  the  same  instant  we  notice  that  a 
little  blood  is  forced  into  these  vessels  only  at  the  height 
of  the  pulse-wave,  after  which  the  vessels  collapse  until 
the  next  cardiac  systole,  so  that  the  ends  of  the  arteries 


84  OPHTHALMOSCOPY. 

are  empty  for  that  space  of  time.  The  euds  of  the  veins, 
of  course,  do  not  show  any  pulsation.  On  the  contrary, 
if  there  is  a  physiologic  venous  pulse  it  usually  subsides 
and  the  ends  of  the  veins  are  less  distended,  the  pulse 
reappearing  only  after  pressure  on  the  eye  is  removed, 
when  the  ends  of  the  veins  swell  out  and  even  the  finer 
vessels  on  the  papilla  appear  more  distended  and  stand 
out  more  distinctly  than  they  did  before  pressure  was 
made  on  the  eye. 

This  intermittent  influx  of  the  arterial  blood  into  the 
vascular  system  of  the  retina  is  observed  also  when  the 
pressure  in  the  interior  of  the  globe  is  raised  by  disease, 
instead  of  artificially  by  means  of  the  finger.  It  occurs 
in  glaucoma  whenever  the  pressure  rises  rapidly  (acute 
glaucoma) ;  it  is  less  noticeable  in  simple  glaucoma  where 
the  rise  of  pressure  is  gradual.  The  intermittent  influx 
is  exactly  the  same  as  when  the  pressure  is  raised  arti- 
ficially. The  pulse-wave  overcomes  the  pressure  on  the 
walls  of  the  vessels  only  at  the  moment  of  its  greatest 
height. 

A  similar  phenomenon  is  said  to  occur  when  there  is 
pressure  on  the  arteria  centralis  retinae  behind  the  bulb, 
as,  for  instance,  in  the  case  of  a  neoplasm. 

Analogous  to  the  arterial  end-pulse-wave  is  a  venous 
end-pulse,  better  described  as  an  intermittent  efflux. 
This  phenomenon  is  somewhat  more  difficult  to  explain. 
As  has  been  said,  tlie  pulsating  movement  is  often  noticed 
in  normal  eyes,  and  then  has  no  significance.  Three  dif- 
ferent explanations  have  been  offered.  Bonders  ^  assumed 
that  the  pressure  in  the  arteries  of  the  interior  of  the  eye 
was  somewhat  heightened  during  the  cardiac  systole,  so 
that  the  ends  of  the  veins  on  the  papilla  were  compressed, 
because  in  them  the  lateral  blood-pressure  is  least  marked. 
As  soon  as  the  cardiac  systole  is  over  the  venous  blood 
flows  off.  Helfreich^  gives  the  following  explanation: 
According  to  investigations  by  Bergmann  and  Cramer  it 

1  Donders,  Arch.  f.  Ophth.,  vol.  i. 

2  Helfreich,  Arch.  f.  Ophth.,  vol.  xxviii. 


THE  NORMAL  EYE-GROUND.  85 

may  be  assumed  that,  owing  to  the  rhythmical  increase  in 
the  amount  of  blood  sent  to  the  arteries  of  the  brain,  the 
blood  is  crowded  out  of  the  cerebral  veins  by  compression 
and  this  gives  rise  to  an  increase  in  the  rate  of  flow  of 
the  venous  blood  from  the  cranium  synchronous  with  the 
pulse.  Hence  we  have  marked  pressure-variations  in 
the  venous  sinuses  of  the  brain.  The  pressure-varia- 
tions in  the  cavernous  sinus  necessarily  influence  the 
movements  of  the  blood  in  the  veins  of  the  orbit  and 
of  the  interior  of  the  eye.  Whenever  the  pressure  in 
the  cavernous  sinus  diminishes,  the  cerebral  blood  is,  as 
it  were,  aspirated,  and  there  results  a  diminution  in  the 
caliber  or  a  partial  collapse  in  the  orbital  veins,  provid- 
ing the  walls  of  the  veins  are  not  so  firmly  adherent  to 
the  surrounding  tissues  as  to  preclude  the  possibility  of 
their  collapsing.  Certain  conditions  are,  however,  neces- 
sary for  the  pulse  to  show  itself,  otherwise  the  phenom- 
enon would  be  constant. 

Both  of  these  theories  in  regard  to  the  origin  of  the 
venous  end-pulse  may  be  utilized,  v.  Schulten  has  sliown 
by  manometric  experiments  that  there  is  a  slight  increase 
of  the  pressure  in  the  interior  of  the  eye  synchronous 
with  the  cardiac  systole.  Anyone  can  satisfy  himself 
with  the  ophthalmoscope  that  a  slight  increase  in  pressure, 
as  by  the  finger,  is  immediately  followed  by  a  diminution 
in  the  amount  of  blood  in  the  ends  of  the  veins  on  the 
papilla.  The  lightest  touch  of  the  finger  rhythmically 
applied  suffices  to  imitate  the  venous  pulse.  On  the 
other  hand,  we  may  believe  with  Helfreich  that  the 
cardiac  diastole  is  accompanied  by  an  increase  in  the  rate 
of  flow  of  the  blood  from  the  orbital  veins  to  the  cavern- 
ous sinus ;  but  whether  this  increase  is  sufficient  to  cause 
jthe  veins  on  the  papilla  to  collapse,  as  contended  by 
Helfreich,  may  be  disputed.  While  it  may  be  admitted 
that  the  blood-pressure  in  these  veins  is  very  low  at  the 
end  of  the  cardiac  diastole,  and  that  the  increase  in  the 
intraocular  pressure  synchronous  with  the  cardiac  systole 
(Bonders)  momentarily  contracts   the  veins    perceptibly 


86  OPHTHALMOSCOPY. 

or  even  causes  them  to  collapse,  it  is  probable  that  the 
damming  back  of  the  venous  blood  from  the  brain 
(Helfreich)  antagonizes  this  contraction  of  the  veins  and 
produces  engorgement  of  their  extremities,  which,  as 
everyone  admits,  manifests  itself  shortly  after  the  cardiac 
systole.  In  this  way  the  actual  conditions  on  which  both 
theories  are  based  are  utilized.  Whether  my  explana- 
tion is  correct  or  not  must  be  decided  by  future  investi- 
gators. 

S.  TUrk^  offers  a  third  explanation  for  the  physiologic 
venous  pulse.  According  to  him  it  is  due  to  a  continua- 
tion of  the  arterial  pulse-wave  through  the  capillaries 
into  the  veins,  a  so-called  progressive  venous  pulse, 
the  pulsatory  dilatation  being  produced  by  the  cardiac 
systole,  as  in  the  arteries.  According  to  him  this  abnor- 
mal prolongation  of  the  pulse-wave  is  made  possible  by 
the  comparatively  high  extra  vascular  pressure  to  which 
the  vessels  in  the  eye  are  subjected. 

A  true  arterial  pulsation  is  seen  in  aortic  insufficiency. 
In  this  condition  the  difference  in  the  blood-pressure  dur- 
ing svstole  and  diastole  in  the  arterial  system  is  abnor- 
mallv  great;  that  is  to  say,  owing  to  the  cardiac  hyper- 
trophy, the  pulse-wave  is  abnormally  high  and  followed 
by  an  abnormal  recession  of  the  wave,  because  the  blood 
flows  back  into  the  heart  through  the  insufficient  valve, 
unless  aortic  stenosis  is  also  present.  Accordingly,  the 
smaller  arteries  and  even  the  capillaries  pulsate  in  this 
disease.  In  well-marked  cases,  we  can  see  not  only  a 
violent  pulsating  of  the  retinal  arteries  and  veins,  but 
even  a  pulsatory  blushing  and  paling  of  the  papilla. 
The  larger  arterial  branches  in  certain  conditions  show  a 
true  pulsation,  both  variation  in  caliber  and  locomotion,  at 
a  considerable  distance  from  the  papilla.  As  a  rule,  the 
veins  in  such  cases  show  pulsation  (variations  of  caliber), 
which  may  even  be  more  marked  than  in  the  arteries. 
But  if  there  is  only  slight  insufficiency  and  but  little 
hypertrophy  of  the  left  ventricle,  or  if  the  cardiac  action 

1  Turk,  Arcli.f.  Ophth.,  vol.  xlviii.  p.  3,  1899. 


THE  NORMAL  EYE-GROUND.  87 

is  merely  weak,  as  when  the  patient  is  at  rest,  the  pulsa- 
tion in  the  retinal  vessels  may  be  absent  or  may  appear 
only  when  the  patient  causes  his  heart  to  work  faster. 
The  intensity  of  the  phenomenon  is  also  diminished  when 
there  is  co-existent  aortic  stenosis.  In  other  forms  of 
heart  disease  the  retinal  vessels  rarely  or  never  exhibit 
pulsation.  An  arterial  pulse  is  occasionally  observed  in 
mitral  insufficiency.  In  mitral  stenosis  I  saw  it  only 
once  in  fifteen  cases.  In  mitral  stenosis  complicated  with 
aortic  insufficiency,  I  saw  it  in  one  case  and  not  in  an- 
other. Even  in  stenosis  of  the  mitral  valve  and  in 
mitral  insufficiency  with  stenosis,  I  did  not  see  any 
pulsation. 

It  appears,  therefore,  that  the  pulse-phenomena  in  the 
eye-ground  are  of  very  little  value  in  the  diagnosis  of 
cardiac  disease.  Besides,  the  detection  of  pulse-phe- 
nomena in  the  eye-ground  is  one  of  the  most  difficult 
things  in  ophthalmoscopy.  To  study  them  carefully  it  is 
well  to  examine  the  patient  on  a  chair  instead  of  in  bed, 
and  to  let  him  lean  his  arm  on  the  table.  The  surgeon 
should,  if  possible,  also  be  seated,  and  support  the  arm 
that  holds  the  mirror  on  the  table.  If  these  precautions 
are  neglected,  the  pulsating  movements  of  the  surgeon's 
arm  or  trunk  will  deceive  him  when  he  looks  Into  the 
eye  and  make  him  think  that  the  vessel  he  is  examining 
is  pulsating.  The  same  error  may  be  produced  by  pul- 
sating movements  in  the  trunk  of  the  patient.  Auto- 
suggestion also  plays  an  important  part.  If  the  observer 
is  very  anxious  to  see  a  pulsating  vessel,  he  will  seem  to 
see  things  pulsate  which  in  reality  do  not  show  a  trace  of 
pulsation. 

It  goes  without  saying  that  these  things  can  be  seen 
only  in  the  direct  method. 


Fig,  1. 


Fig.  1.  Normal  Eye-ground. — A  moderately  pigmented 
eye-ground,  the  pigmentation  being  strongest  about  the  optic 
nerve  and  behind  the  macula  and  its  surroundings.  At  the 
periphery  is  seen  the  mottled  appearance  due  to  the  increased 
amount  of  pigmentation  in  the  intervascular  spaces  of  the 
choroid.  In  front  of  the  latter,  in  the  center,  are  the  retinal 
vessels  with  their  lines  of  reflection.  The  arteries  are  lighter 
in  color  than  the  veins.  The  optic  nerve  possesses  a  moder- 
ately deep  excavation  with  a  correspondingly  light  color,  a 
scleral  ring,  and  a  somewhat  blurred  choroidal  ring. 

Inexperienced  observers  often  fall  into  the  error  of  mis- 
taking the  dark  intervascular  spaces  in  the  normal  eye- 
ground,  or  the  bright  striations  between  the  dark  islands  for 
pathologic  conditions,  and  are  thus  led  to  make  the  diagnosis 
of  disseminated  choroiditis.  It  is,  therefore,  well  to  study  the 
appearances  of  the  normal  eye-ground,  especially  the  appear- 
ance at  the  periphery. 


Fig  2,  a.  Longitudinal  Section  of  a  Normal  Papilla  stained  with 
Weigert's  stain,  showing  how  the  nerve-fihers  of  the  optic  nerve  lose 
their  medullary  sheath  (black  color)  as  they  pass  through  the  lamina 
cribrosa  and  thus  diminish  the  caliber  of  the  optic  nerve.  The  hha^d  in 
the  vessels  of  the  optic  nerve,  the  retina,  and  choroid,  as  well  as-in  the 
neighborhood  of  the  optic  nerve,  wherever  it  is  present,  is  also  stained 
black.  In  the  region  of  the  papilla  the  central  vessels  {V.  c.)  arelii  part 
imbedded  and  appear  like  round  cells. 

When  the  nerve-fibers  retain  their  medullary  sheath  until  they  reach 
the  retina — a  condition  which  is  constant  in  the  rabbit  and  occurs  occa- 
sionally in  man,  although  only  to  a  slight  degree — a  white  radiation 
about  the  papilla  is  produced  which  is  represented  in  Fig.  6,  a,  b,  c.  The 
meduUated  nerve-fibers  then  appear  glistening  white  in  the  ophthalmo- 
scopic image.  They  are  not  transparent,  and  therefore  obscure  the  retinal 
vessels  in  places. 

In  this  picture  there  is  a  well-marked  excavation  where  the  nerve- 
fibers  diverge  after  passing  through  the  lamina  cril)rosa,  differing  in  this 
respect  from  the  following  picture,  where  the  divergence  is  very  slight 
(cf.  Fig.  2,  6). 

In  the  ophthalmoscopic  image  this  appears  as  a  pallor  of  the  center  of 
the  papilla,  or  the  so-called  physiologic  excavation — paler  because  the 
white,  glistening  connective  tissue  of  the  lamina  cribrosa  is  seen  more 
j  plainly  through  the  diverging  nerve-fibers. 

The  size  of  the  excavation  varies  greatly  within  physiologic  limits. 
When  it  is  large,  it  is  often  difficult  to  decide  whether  we  have  to  deal 
with  a  physiologic  or  pathologic,  that  is  to  say,  glaucomatous  cup. 

V.  c,  central  vessels ;  Pig.,  pigment-epithelium  of  the  retina. 

Magnified  14  times. 

Fig.  2,  b.  Longitudinal  Section  through  a  Normal  Papilla  showing 
Almost  No  Excavation.— The  head  of  the  nerve  barely  projects  above 
the  level  of  the  retina,  so  that  there  is  only  a  very  slight  papilla. 
Behind  the  depression,  which  is  very  shallow,  the  arteria  et  vena  cen- 
tralis retinae  can  be  traced  for  a  short  distance.  Stained  with  hema- 
toxylin and  eosin.  Nuclei  and  granules  of  the  retina  violet;  connective 
^sue  reddish. _. 

V.  c,  central  vessels;  J.,  subdural  space  of  the  optic  nerve  between  the 
dural  {D.),  or  rather  arachnoidal,  and  the  pial  (P.)  sheaths,  traversed  by 
trabeculse  of  connective  tissue  from  the  arachnoidal  sheath  (cf.  Fig.  21). 

Magnified  14  times.^ 


^  In  the  figures,  which  accurately  reproduce  the  microscopical  sections, 
intervals  appear  here  and  there  between  the  retina  and  the  choroid  and 
between  the  choroid  and  the  sclera.  It  is  impossible  to  avoid  this  in  pre- 
paring the  specimens,  but  we  must,  of  course,  imagine  the  various  layers 
in  contact  with  each  other.  The  same  applies  to  many  of  the  following 
figures. 


a 


Corpus   Pitreum 


Chor.^,  . 


,.■-■:-._,  Retina 

c       ,.«<»^'' 


i  •  Lamina  cribrosa 
New.  opticas 


c. 


Skier  a 


P. 


Corpus  Ditreum 


V.c. 


^V.''^-^^ 


Retina 
^-r  Chor. 


;U  :  \' 


■wm'- 


y-;\- 


D. 


J. 


Nervus  opticus 

Fig.  2. 


Fig.  3.  Section  through  the  Retina,  Choroid,  and  Con- 
tiguous Sclera  in  a  Normal,  Moderately  Pigmented  Eye  at 

a  distance  of  several  millimeters  from  the  macula  lutea. — 
The  tissues  were  fixed  by  immersing  the  freshly  enucleated 
globe  in  a  warm  saturated  bichloride  solution,  hardened  with 
alcohol,  and  stained  with  hematoxylin  and  eosin. 

The  preparation  with  the  power  used  for  this  illustration 
does  not  show  the  individual  fibers  of  the  nerve-fiber  layer. 
In  the  inner  reticular  layer  Miiller's  supporting  fibers  are 
barely  seen  as  fine  red  lines.  In  the  intern uclear  layer  the 
outer  reticular  layer  is  easily  distinguished  from  the  outer 
fiber  layer.  In  the  layer  of  rods  and  cones  the  outer  seg- 
ments of  these  structures  are  recognized  by  the  fact  that  they 
are  somewhat  bent  (probably  an  artefact),  while  the  inner 
segments  are  placed  vertically  on  the  external  limiting  mem- 
brane. The  nuclei  of  the  pigment-epithelium  of  the  retina 
are  plainly  seen.  The  blood  in  the  choriocapillaris  and  in 
the  other  vessels  of  the  choroid,  as  well  as  in  those  in  the 
anterior  layer  of  the  retina,  is  stained  bright  red  bj  the  eosiih 

In  the  choroid  the  pigment-cells  are""  found  chiefly  in  the 
intervals  between  the  larger  vessels  (corresponding  to  the 
pigmented  intervascular  spaces  of  the  ophthalmoscopic  image  ; 
cf.  Fig.  5,  6,  for  instance).  Only  that  portion  of  the  sclera 
which  is  contiguous  with  the  choroid  is  seen  in  the  pictures 
of  Fig.  2.  J, 

1,  Nerve-fiber  layer ;  2,  gan§l|Qn;cell  layer ;  3,  inner  retic-  ^  ^^^ 
ular  layer  ;  -^,  inner  nuclear  layer ;   5,  internuclear  (outer 
reticular)  layer ;    6\  outer  nuclear  layer ;    7,  layer  of   rods 
and  cones ;  8,  retinal  pigment-epithelium  ;    F.,  retinal  vessels. 
^  Magnified  214  times. 


Fig.  4.  Normal  Eye-ground. — The  eye,  being  that  of  a 

blonde,  possesses  less  pigment  than  that  shown  in  Fig.  1. 
Note  especially  that  the  pigment-epithelium  of  the  retina  is 
much  more  transparent,  so  that  the  vessels  of  the  choroid  are 
very  distinct.  As  the  choroid  also  possesses  a  small  amount 
of  pigment,  the  intervascular  spaces  are  lighter  instead  of 
darker  than  the  vessels.  The  fovea  in  this  case  is  red,  and 
the  reflex  of  the  center  of  the  fovea  is  not  seen  on  account 
of  the  pale  color  of  the  eye-ground.  In  the  optic  nerve  the 
excavation  and  the  choroidal  and  scleral  rings  are  very 
marked. 

To  understand  the  appearances  of  a  normal  eye-ground  a 
knowledge  of  the  normal  anatomy  of  these  parts  is  indis- 
pensable. The  most  important  anatomic  details  are  illus- 
trated in  Figs.  2,  a  and  6,  3,  and  14,  a,  b,  c. 


Fig.  4. 


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CONGENITAL  DEFECTS. 

(Figs.  7-11.) 

Fig.  7.  Congenital  Circumscribed  Defect  of  the  Choroid 
(Coloboma  Choroideae)  in  the  lower  part  of  the  figure  (erect 
image  reduced  to  the  size  of  the  inverted  image). 

The  defect  exposes  the  sclera  and  has  a  roundish  out- 
line, its  upper  border  being  at  a  distance  of  three  optic- 
nerve  diameters  from  the  papilla.  Along  this  border  a  small 
amount  of  choroidal  tissue  is  still  present,  but  farther  down 
the  membrane  is  represented  only  by  a  few  remnants  in  the 
form  of  pigment-spots  and  a  few  vessels.  Some  of  the  retinal ' 
vessels  are  seen  on  the  surface  of  the  coloboma.  The  rest  of 
the  eye-ground  is  normal. 

These  defects  of  the  choroid  in  the  lower  segment  of  the 
eye  have  been  attributed  to  persistence  and  failure  to  unite 
of  the  fetal  cleft.  This  explanation,  though  simple,  is  not  quite 
adequate.  The  fetal  cleft  lies  in  the  region  of  the  optic  vesi- 
cle, which  later  becomes  the  retina,  but  as  a  matter  of  fact 
the  retina  is  not  absent  in  the  region  of  the  coloboma,  since 
both  in  this  and  in  the  following  figure  retinal  vessels  are 
seen  traversing  the  coloboma.  The  defect  is  therefore  not  in 
the  optic  vesicle  and  its  cleft,  but  in  the  region  of  the  meso- 
derm or  of  its  derivative — the  choroid.  These  inferior  colo- 
bomas  and  other  congenital  defects  (cf.  the  following  figures) 
are  probably  due  in  many  cases  to  intra-uterine  disease,  and 
it  is  probable  that  the  fetal  cleft  plays  but  a  secondary  role 
in  the  first  group,  consisting  of  inferior  coloboma  of  the  iris 
and  choroid. 


Fig.  8,  a.  Congenital  Circumscribed  Defect  of  the  Choroid 
and  Malformation  of  the  Optic  Nerve  (Coloboma  Choroideae 
et  Nervi  Optici)  (erect  image  reduced  to  the  size  of  the 
inverted  image). 

The  choroidal  defect  in  this  case  surrounds  the  optic  nerve, 
which  is  much  ^creased  in  size.  The  manner  in  which  the 
vessels  leave  the  optic  disk  is  altogether  abnormal.  The 
optic  nerve  and  the  portion  of  the  sclera  joining  it  below 
are  excavated  (ectatic),  the  larger  cavity  containing  three 
smaller  diverticula,  two  oval  and  one  round  (staphylomata). 
A  few  retinal  and  choroidal  vessels  are  seen  in  the  region  of 
the  coloboma. 

Fig.  8,  b.  Congenital  Defect  of  the  Pigment-epithelium 
of  the  Retina  in  the  Region  of  the  Macula  Lutea. — The 
two  whitish  patches  correspond  to  defects  of  the  choroidal 
tissue  which  expose  the  sclera.  They  are  traversed  by  a  few 
choroidal  vessels.  At  the  temporal  border  of  the  optic  disk 
there  is  another  defect  of  the  choroid  having  the  form  of  a 
triangle  with  the  apex  broken  off.  In  the  orange-colored 
areas,  where  the  pigment-epithelium  is  absent,  irregular  lines 
of  pigmentation  are  seen.  The  rest  of  the  eye-ground  is 
normal.     The  other  eye  shows  similar  changes.  J^ 

The  patient  is  a  young  woman  suffering  from  hereditary 
syphilis. 


Fig.  8. 


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Fig.  13,  A. 


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tlie  ci'rebellum  (de  >Sch\\einitzi. 


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2.  ty*  s::  ZL  EL-  B  p  tr  -• :::  2  2  5 


Fig.  14,  a.  Horizontal  Section  of  a  Normal  Macula  Lutea, 

almost  exactly  through  the  fovea  centralis  (F.  c). — The  freshly- 
enucleated  globe  was  immersed  in  a  warm  saturated  bichlorid 
solution  and  hardened  in  alcohol.  The  sections  were  stained 
with  hematoxylin  and  eosin.  The  walls  of  the  excavation  are 
probably  not  so  steep  in  the  living  subject  as  they  appear  in 
this  preparation.  On  the  floor  of  the  excavation  the  pigmen- 
tary layer  is  reduced  to  the  slender  cones  with  their  fibers 
and  nuclei.  In  the  internuclear  layer  the  fibers,  owing  to  the 
manipulation  of  the  specimen,  diverge  somewhat  (better  seen 
in  Fig.  14,  c),  which  makes  the  walls  of  the  excavation  appear 
steeper  than  normal. 

Magnified  14  times. 

Fig.  14,  b,  shows  the  outlines  of  the  same  preparation, 
seen  under  the  same  power  as  the  following  picture.  Magni- 
fied 30  times. 

Fig.  14,  c.  Another  section  from  the  same  specimen  through 
the  excavation  and  its  surroundings,  taking  in  the  adjoining 
choroid  and  sclera,  under  a  higher  power  than  Fig.  14,  a. 
(On  the  floor  of  the  excavation  there  is  a  slight  prominence 
which  is  an  artefact.)  Next  to  the  pigment-epithelium  we  see 
the  choriocapillaris.  On  the  posterior  surface  of  the  sclera 
are  seen  several  transverse  and  oblique  sections  of  posterior 
ciliary  vessels  (  F.).     Stain  the  same  as  in  Fig.  14,  a. 

The  picture  incidentally  shows  the  relative  thickness  of  the 
three  membranes — retina,  choroid,  and  sclera. 

Magnified  30  times. 

In  both  sections  we  see  at  the  margin  of  the  fovea  centralis 
the  internal  limiting  membrane  (margo  limitans  internus), 
which  in  the  specimen  has  become  somewhat  separated  from 
its  foundation. 


Corpus   vitr. 


a 


Retina 


Corpus    vitr. 
Ee. 


Retina 


?^]mr 


-^i^^^ 


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V 


V 


Fig.  14. 


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h 


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Retina 


Corpus  vitreum 


E 


^»':^-T~:/^ri-r^-fi' 


Nervus  opticus 


J. 


„  Corp.  vitr. 


i  ft  f'i  liU'i'   I' 


I- 

Fig.  15. 


Fig.  15,  a.  Longitudinal  Section  through  the  Papilla  in 
Neuritis  (Papillitis,  Choked  Disc),  due  to  brain-tumor  (sar- 
coma of  the  temporal  lobe). — Stained  with  hematoxylin. 
The  papilla  in  this  specimen  is  moderately  swollen.  The 
swelling  may  be  much  more  marked  in  these  cases — even 
more  marked  than  in  the  following  picture.  The  separation 
of  the  retina  from  the  choroid  is  an  artefact.  (See  Ed.  note 
opposite  Fig.  13.) 

There  is  a  heavy  inflammatory  infiltration  (proliferation 
of  nuclei)  between  the  lamina  cribrosa  and  the  anterior  sur- 
face of  the  papilla.  In  the  subdural  space  (J.)  occasional 
areas  of  inflammatory  exudate  (E.)  are  also  seen.  The  trunk 
of  the  optic  nerve,  in  the  center  of  which  a  third  segment  of 
the  central  vessel  is  visible,  is  also  the  seat  of  moderately 
well-marked  inflammatory  proliferation. 

E.,  inflammatory  exudate  in  the  subdural  space  of  the 
optic  nerve ;  J.,  subdural  space ;  B.,  retina. 

Magnified  14  times. 

In  this  case  the  papilla  and  surroundings  first  presented 
the  picture  seen  in  Fig.  12,  a,  and  later  that  seen  in  Fig. 
13,5. 

Fig.  15,  b.  Longitudinal  Section  through  the  Papilla  in 
Neuritis  and  Papillitis  from  brain-tumor  with  purulent  men- 
ingitis, terminating  fatally  in  spite  of  trephining. — Stained 
with  hematoxylin  and  eosin.  The  swelling  of  the  papilla  is 
greater  than  in  the  foregoing  case  and  would  be  more  pro- 
nounced were  it  not  for  the  separation  of  the  retina  from  the 
choroid  (artefact). 

The  lateral  extension  of  the  swelling  beyond  the  border  of 
the  papilla,  which  in  the  ophthalmoscope  produces  the  so- 
called  enlargement  of  the  papilla  (see  Figs.  13,  17,  and  18), 
is  clearly  seen.  We  also  see  without  difficulty  a  marked 
engorgement  of  the  vessels,  especially  of  the  veins  of  the 
papilla  (F.  c.)  and  hemorrhages  (H.)  into  the  tissues  of  the 
papilla.  There  is  also  some  inflammatory  exudate  in  the 
subdural  space. 

F.  c,  central  vessels;  E.,  exudate  in  the  subdural  space; 
Ch.y  choroid  ;  i?.,  retina  ;  H.,  hemorrhages. 

^lagnified  14  times. 

The  ophthalmoscopic  image  in  this  case  resembles  that 
shown  in  Figs.  17  and  18. 


Fig.  16.  Inflammation  of  the  Optic  Nerve  and  the  Adja- 
cent Portion  of  the  Retina  in  Syphilis  (so-called  Specific 
Neuroretinitis). — There  is  a  marked  blurring  of  the  optic 
nerve  and  its  surroundings,  due  in  part  to  the  diffuse  central 
opacity  of  the  vitreous.  The  peripheral  portions  of  the  eye- 
ground  in  this  case  are  not  diseased,  but  in  many  cases  they 
are  the  seat  of  foci  of  disseminated  choroiditis  in  various 
stages.  The  picture  before  us  is  characteristic,  or  at  least 
strongly  suggestive,  of  syphilis. 

The  opacity  may  disappear  under  appropriate  treatment, 
but  usually  leaves  a  more  or  less  pronounced  atrophic  dis- 
coloration of  the  nerve.  Minute  foci  of  choroiditis  may 
develop  in  the  periphery  in  the  course  of  the  disease. 


V 


\ 


/ 


y 


Fig.  16. 


Fig.  17. 


Fig.  17.  Intense  Inflammation  of  the  Optic  Nerve  (Papil- 
litis) after  meningitis  caused  by  a  blow  on  the  head. — The 
inflammation  in  both  eyes  has  led  to  marked  infiltration  of 
the  tissues  of  the  nerve,  manifesting  itself  in  grayish-white 
patches  and  striae  on  the  papilla  and  surrounding  portions  of 
the  retina,  and  in  the  hemorrhages  at  the  lower  outer  border 
of  the  discolored  areas.  The  diameter  of  the  nerve  is  enlarged 
and  the  nerve  itself  moderately  swollen  and  prominent.  Owing 
to  the  presence  of  inflammatory  product  in  the  tissues  of  the 
nerve,  the  venous  flow  from  the  retina  is  impeded  and  the 
veins  are  therefore  distended  and  tortuous  (patient  belonging 
to  Prof.  Eichhorst's  clinic). 

The  microscopic  appearance  corresponding  to  this  picture 
would  be  about  the  same  as  that  shown  in  Fig.  13,  6. 


1 


\A^ 


1^' 


Fig.  18.  Marked  Inflammation  and  Congestion  of  tlie 
Optic  Nerve  in  Orbital  Tumor. — Exophthalmos  (protrusion) 
was  present.  The  intraocular  extremity  of  the  optic  nerve 
shows  marked  inflammatory  and  edematous  swelling  in  the 
picture.  The  inflammatory  infiltration  appears  as  a  whitish 
striation.  The  veins  of  the  retina  are  very  much  congested 
and  numerous  hemorrhages  into  the  retina  have  occurred  in 
consequence.     The  retinal  arteries  are  moderately  distended. 


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'Veil. 

Arteria  central. 

Vena  centralis 
Neruus  opticus 


Retina, 
Chor. 


Sklera 


Corp.  vitr. 


j^jRetina 


^■'-  i~#^ 


Chorioidea 
Sklera 


^^•^ 


Neruus  opticus 

Fig.  21. 


Fig.  21,  a.  Longitudinal  Section  through  the  Entrance  of 
the  Optic  Nerve  in  Partial  Atrophy  (of  the  Optic  Nerve). — 
Staiued  by  Weigert's  method,  which  colors  the  medullary 
sheaths  a  bluish-black.  In  the  atrophic  left  half  of  the 
nerve-trunk  the  medullary  sheaths  are  altogether  absent. 
Owing  to  the  partial  atrophy  and  consequent  diminution  in 
the  volume  of  the  nerve,  the  subdural  space  is  somewhat 
broader  than  normal  and  the  arachnoidal  sheath  is  plainly 
visible.  The  papilla  is  already  distinctly  flattened  from 
atrophy. 

D.,  dural  sheath  ;  A.^  arachnoidal  sheath  ;  P.,  pial  sheath  ; 
V.  cil.y  ciliary  vessel. 

Magnified  14  times. 

Fig.  21,  h.  Longitudinal  Section  through  the  Disk  in 
Total  Atrophy  of  the  Optic  Nerve,  stained  after  Weigert. — 
All  the  medullary  sheaths  are  wanting.  The  trunk  of  the 
nerve  is  thinner  even  than  in  the  preceding  case.  The  papilla 
shows  a  distinct  atrophic  excavation,  on  the  floor  of  which  the 
lamina  cribrosa  is  laid  bare.  A  portion  of  the  arteria  cen- 
tralis {A.  c.)  is  seen  in  this  section. 

This  is  the  microscopic  appearance  that  corresponds  to  the 
ophthalmoscopic  picture  shown  in  Fig.  20,  h.  The  patient 
from  which  the  specimen  was  taken  presented  at  the  time  of 
his  first  examination  a  beginning  gray  atrophy  like  the  pict- 
ure of  Fig.  20,  a,  and  later  advanced  gray  discoloration  of 
the  papilla,  as  shown  in  Fig.  23.  Later  he  developed  pro- 
gressive paralysis  and  died  in  the  insane  asylum.  The  pos- 
terior half  of  the  globe  was  kindly  given  me  by  Prof.  Forel. 

Magnified  14  times. 


Fig.  22.  Atrophy  of  the  Optic  Nerve  due  to  Increased 
Intraocular  Tension  (Glaucoma). — The  entire  end  of  the 
nerve  shows  marked  excavation  and  dark  discoloration. 
The  lamina  cribrosa  is  pushed  back  and  plainly  visible 
owing  to  the  disappearance  of  the  nerve-fibers.  The  cho- 
roid near  the  optic  nerve  is  atrophied  and  forms  a  pale 
areola,  also  known  as  the  glaucomatous  halo.  The  retinal 
vessels  are  sharply  bent  at  the  edge  of  the  excavation  and 
dip  down  to  the  floor,  where  some  of  them  become  visible  on 
the  lamina  cribrosa.  At  first  the  veins  are  congested  and 
dilated,  but  now  the  vessels  of  the  retina  are  also  beginning 
to  atrophy.  Parallactic  dislocation  and  measurement  in  the 
erect  image  (see  Introduction)  reveals  a  distinct  movement 
of  the  edge  of  the  excavation  in  front  of  the  floor,  and  the 
excavation  is  found  to  be  about  2  mm.  deep  (6  D  difference 
of  refraction  between  the  edge  and  the  floor). 

The  glaucomatous  changes  in  the  end  of  the  nerve  are 
illustrated  in  Fig.  24,  c  and  d. 


V 


Fig.  22. 


s  p  I  &§  -I  2-1;?  S  ^ 
2§^a3g8p§|i2 

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i  S  S-i  i  »  o-g  ETS  o-S^ 

gg  »  2  ^  ^       «  3-3  »-^. 
oS^<S^§       <o^3g; 


Fig.  24,  a.  Meridional  Section  through  the  Region  of  the 
Angle  of  the  Anterior  Chamber  in  a  Normal  Eye. — The  cil- 
iary body  became  loosened  from  the  sclera  during  the  prep- 
aration of  the  specimen,  but  the  position  of  the  iris  is  approx- 
imately correct,  so  that  the  angle  between  its  ciliary  attachment 
and  the  cornea  is  well  seen. 

C  V.  c,  circulus  venosus  ciliaris,  or  Schlemm's  canal,  or,  in 
the  new  nomenclature  of  the  Anatomical  Society,  sinus  veno- 
sus sclerse  ;  L.p.,  ligamentum  pectinatum. 

Magnified  14  times. 

Fig.  24,  h.  Section  through  the  Same  Region,  showing  the 
Obliteration  of  the  Angle  of  the  Anterior  Chamber  which 
often  occurs  in  Glaucoma. — As  the  aqueous  humor  leaves  the 
bulb  through  the  angle  of  the  anterior  chamber,  obliteration 
of  that  angle  obstructs  its  outflow  and  thus  explains  the  in- 
creased pressure  in  glaucoma.  The  fluid  is  retained  within  the 
bulb  and  this  gives  rise  to  the  further  symptoms  of  glaucoma, 
especially  the  excavation  of  the  head  of  the  nerve  by  pressure, 
which  is  shown  in  the  two  following  pictures. 

Magnified  14  times. 

Fig.  24,  c.  Longitudinal  Section  through  the  Head  of  the 
Optic  Nerve  in  Advanced  Glaucoma. — The  excavation  of  the 
end  of  the  nerve  due  to  the  increased  intraocular  pressure  is 
well  marked.  The  papilla  is  replaced  by  a  concavity  with  steep 
sides,  the  floor  of  which  is  formed  by  the  lamina  cribrosa  and 
the  nerve-fibers  which  have  not  as  yet  become  atrophied  by 
the  pressure  and  kinking  at  the  edge  of  the  papilla. 

Fig.  24,  d.  Longitudinal  Section  through  the  Head  of  the 
Optic  Nerve  in  a  still  more  Advanced  Stage  of  Glaucoma, 
showing  the  diminution  in  size  of  the  trunk  of  the  optic  nerve 
produced  by  atrophy  of  the  nerve-fibers  and  the  increase  in 
the  width  of  the  subdural  space  [of  the  optic  nerve]. — In  this 
section  the  kettle-shaped  excavation  on  the  end  of  the  nerve 
that  occurs  so  often  in  glaucoma  is  quite  pronounced.  As  the 
nerve  becomes  smaller  between  the  lamina  cribrosa  and  its 
anterior  extremity,  as  shown  in  Fig.  2,  a,  the  glaucomatous 
excavation  in  which  the  lamina  cribrosa  is  pushed  backward 
by  the  abnormal  pressure  upon  it  is  very  apt  to  take  on  this 
kettle  shape,  that  is  to  say,  to  become  narrower  in  front  than 
behind.  To  a  limited  degree  this  may  be  seen  in  the  pre- 
ceding figure. 

Fig.  24,  c  and  d^  magnified  14  times. 


Sklent 

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Corpus  ciliare         ^^^ 


:-'!^^'^-;' 


V;^;1f^- 


Cornea  i^ 

Endothel 
Jris 


etina, 
Chorioidea 

__  Ski  era 


Nerv.  opticus 


Nerp.  opticus 
Fig.  24. 


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Fig.  26,  a.  Section  through  the  Retina  in  Retinitis  Albn* 
minurica. — Stained  with  hematoxylin  and  eosin. 

The  ravages  produced  by  the  disease  will  be  at  once  seen 
by  comparison  with  Fig.  3.  Numerous  hemorrhages  stained 
red  by  the  eosin  occupy  the  anterior  layers  of  the  retina.  In 
the  internuclear  (outer  reticular)  layer  we  find  between  the 
fibers  numerous  gaps  formed  by  edema  and  exudation.  In 
one  spot  (stained  very  dark)  is  seen  a  mass  consisting  prob- 
ably of  fibrinous  exudate  (cf.  Fig.  27). 

Similar  gaps  are  seen  in  the  nerve-fiber  layer  which  con- 
tains numerous  varicose  nerve-fibers  shown  under  a  higher 
power  in  Fig.  26,  b  and  c. 

Magnified  20  times. 

The  section  corresponds  approximately  to  the  ophthalmo- 
scopic pictures  shown  in  Fig.  28,  a  and  b.  The  white  foci  in 
the  retina  correspond  anatomically  to  the  masses  of  fibrinous 
exudate  represented  in  Figs.  26  and  28,  or  to  varicose  nerve- 
fibers  that  are  often  aggregated  in  bundles,  or  possibly  to 
collections  of  wandering  leukocytes  and  tissue-cells  in  a  more 
or  less  advanced  stage  of  fatty  degeneration.  The  fatty  de- 
generation is  not  seen  in  the  specimen,  which,  however,  shows 
masses  of  emigrated  lymph-corpuscles  scattered  here  and  there 
among  the  tissues. 

Fig.  26,  b  and  c.  Varicose  Nerve-fibers  from  the  section 
shown  in  Fig.  26,  a,  under  a  higher  power. — Along  the 
spindle-shaped  thickenings  of  the  nerve-fibers  (stained  violet 
by  hematoxylin)  are  found  nuclei  of  lymph-corpuscles  or 
inflammatory  leukocytes. 

Magnified  112  times. 


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Pig.Epith. 
J. 


Sklera 


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Fig.  27. 


Fig.  27.  Alterations  in  the  Retina  in  Retinitis  Albu- 
minnrica. — a  represents  a  section  through  the  retina,  cho- 
roid, and  part  of  the  sclera.  The  interval  between  the 
layer  of  rods  and  cones  and  the  pigment-epithelium,  and 
the  separation  of  the  internal  limiting  membrane  from  the 
nerve-fiber  layer  are  artefacts. 

b  represents  an  adjoining  portion  of  the  same  specimen. 
In  the  nerve-fiber  layer  and  in  the  ganglion-cell  layer  leuko- 
cytes are  seen  scattered  through  the  tissues,  especially  in 
Fig.  27,  b.  The  lymph-spaces  are  wider  than  normal,  owing 
to  edema  and  the  presence  of  amorphous  exudate.  The  in- 
ternuclear  (outer  reticular)  layer  contains  a  network  of  tough 
fibrinous  exudate  stained  red  by  eosin.  In  Fig.  27,  6,  an 
amorphous  fragment,  similar  to  that  shown  in  Fig.  26,  is  seen 
in  the  midst  of  the  fibrin.  The  tissues  of  the  internuclear 
(outer  reticular)  layer  are  likewise  edematous  (larger  gaps 
in  the  tissue).  The  layer  of  rods  and  cones  is  degenerated 
and  granular,  the  elements  being  widely  scattered  in  places. 
The  choroid  is  the  seat  of  a  pronounced  inflammatory  in- 
filtration (J.).  The  blood-vessel  V.,  in  Fig.  27,  a,  shows  very 
little  inflammatory  thickening,  in  marked  contrast  to  the 
blood-vessel  F.,  in  Fig.  27,  c,  the  walls  of  which  are  greatly 
increased  in  thickness  and  contain  pigment-granules. 

1,  Layer  of  nerve-fibers  and  ganglion-cells ;  ^,  inner  retic- 
ular layer;  3,  inner  nuclear  layer;  4,  internuclear  (outer 
reticular)  layer ;  5,  outer  nuclear  layer ;  6,  layer  of  rods  and 
cones ;  7,  choroid  ;  8,  sclera. 

a  and  b  magnified  122  times ;  c,  150  times. 


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Fig.  31. 


Fig.  31.  Changes  in  the  Eye-ground  in  Pernicious  Ane- 
mia.— The  eye-ground  is  paler  than  normal.  The  disk  is 
anemic  and  considerably  lighter  in  color.  The  dilatation  of 
the  arteries  is  slight,  that  of  the  veins  marked.  The  retina 
contains  numerous  hemorrhages ;  some  of  them  are  pale  in 
the  center,  which  is  rather  characteristic  of  pernicious  ane- 
mia, although  it  also  occurs  in  other  forms  of  retinal  hemor- 
rhages. A  few  white  patches  are  also  seen  near  the  optic 
nerve.  The  patient,  who  belonged  to  Prof.  Eichhorst's  clinic, 
died  soon  after  the  picture  of  the  eye-ground  was  made. 

Fig.  67  shows  a  microscopic  section  of  an  area  of  the  retina 
containing  hemorrhages  of  this  kind. 


Fig.  32.  Obstruction  of  the  Central  Artery. — The  edges 
of  the  optic  disk  are  obscured  by  a  thick  white  opacity  of 
the  retina,  which  extends  over  the  entire  region  of  the  poste- 
rior pole.  The  vessels  in  the  neighborhood  of  the  optic  nerve 
are  indistinct  in  places  as  if  they  were  interrupted,  while  in 
the  macular  region  the  minute  retinal  vessels  appear  espe- 
cially distinct.  In  the  middle  of  the  foveal  region  we  see  a 
cherry-red  circular  patch,  not  due  to  hemorrhage,  but  to  a 
thinning  of  the  retina,  allowing  the  choroid  to  be  seen 
through  it,  the  red  color  being  intensified  by  contrast  with 
the  white  surroundings.  The  retinal  arteries,  which  at  first 
were  contracted,  have  now  regained  their  normal  caliber 
fairly  well,  but  they  are  still  narrower  than  the  veins.  The 
blood-column  in  the  arteries  is  interrupted  in  places.  At  the 
periphery  the  retina  is  normally  transparent,  so  that  the  pig- 
mented inter  vascular  spaces  of  the  choroid  are  plainly  seen. 

The  obstruction  of  the  central  artery,  which  is  the  cause 
of  this  ophthalmoscopic  image,  was  formerly  always  attrib- 
uted to  embolism.  In  my  opinion  the  cause  of  the  circulatory 
disturbance  is  much  oftener  thrombosis  or  obliterating  endar- 
teritiSj  embolism  being  very  rare. 


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-•    ^'i  ^  iri.^  a"  S,=  ^sg,  ^  I  2. 

c       =^0  Jc^oP^<^g^5,  5.^5^ 


Fig.  34.  Obstruction  of  the  Superior  Temporal  Artery  of 
the  Retina  by  Thrombosis,  Obliterating  Endarteritis,  or 
Embolism. — The  retina  is  cloudy  in  the  distribution  of  the 
arterial  branch.  The  site  of  the  obstruction  cannot  be 
clearly  seen.  The  obstructed  vessel  contains  nearly  as 
much  blood  as  a  normal  vessel.  The  opacity  of  the  retina 
is  most  sharply  defined  toward  the  macula,  where  it  is  also 
most  intense,  as  is  also  usually  the  case  in  obstruction  of  the 
central  artery. 

The  condition  was  found  in  an  old  man  who  was  suffering 
from  arterial  sclerosis  and  later  died  of  cerebral  apoplexy. 


Fig.  35.  Recurring  Hemorrhages  in  the  Retina  and  Vit- 
reous in  a  Young  Individual  (direct  method). — Later,  hem- 
orrhage into  the  vitreous  also  occurred  and  it  became  very- 
difficult  to  see  the  eye-ground.  The  cause  of  the  process  was 
never  determined.  The  urine  contained  no  albumin,  hence 
the  stellate  figure  in  the  macula  cannot  be  attributed  to  albu- 
minuria. A  vein  in  the  nasal  portion  presents  white  mark- 
ings. The  retina  contains  numerous  hemorrhages  of  various 
sizes.  A  large  hemorrhage  above  the  posterior  pole,  which 
does  not  alter  its  form,  has  sent  blood  down  to  the  macular 
region  where  the  blood,  being  fluid,  forms  a  horizontal  layer. 
When  the  head  is  inclined  to  one  side  the  level  of  this  col- 
lection of  blood  immediately  assumes  the  corresponding  angle, 
showing  that  we  have  to  deal  with  a  sacculated  hemorrhage 
between  the  vitreous  and  the  retina. 

These  preretinal  hemorrhages  are  often  situated  immedi- 
ately in  front  of  the  fovea  of  the  retina  and  usually  produce 
a  small  round  reflex,  which  absolutely  resembles  the  small 
fovea  reflex.  In  my  opinion  the  reflex  may  be  explained  as 
follows :  the  portion  of  the  vitreous  lying  in  front  of  the  retinal 
fovea — representing  a  cast  of  the  retinal  fovea — retains  its 
shape  and  dips  down  into  the  hemorrhage  in  the  same  way  as 
it  dips  down  normally  into  the  fovea.  Thus,  it  forms  a  depres- 
sion in  the  hemorrhage,  which  causes  a  reflex  similar  to  that 
^f  the  retinal  fovea. 


Fig.  36.  Syphilitic  Disease  of  the  Retinal  Arteries. — In 
the  lower  left-hand  portion  of  the  picture,  corresponding  with 
the  distribution  of  the  diseased  arterial  trunk,  the  retina  is 
cloudy  and  covered  with  numerous  hemorrhages.  The  dis- 
ease of  the  arterial  walls  manifests  itself  in  various  places  in 
this  region  in  the  form  of  white  lines  which  accompany  the 
blood-column.  In  places  the  blood-column  is  entirely  ob- 
scured by  the  walls  which  have  become  opaque.  In  the 
lower  right-hand  portion  of  the  picture  there  are  also  a 
large  number  of  hemorrhages,  but  the  retina  is  not  cloudy 
and  no  vascular  changes  are  visible.  At  the  opposite  border 
of  the  picture  (to  the  left  and  above)  is  seen  an  artery  with 
changes  in  its  walls  without,  in  this  case,  either  hemorrhages 
or  opacity  of  the  retina.  The  retina  probably  does  not  be- 
come cloudy  unless  the  disease  leads  to  complete  occlusion  of 
the  vessels  and  cuts  off  all  the  blood-supply  through  the  col- 
laterals. Hemorrhages  may  be  present  even  when  the  arte- 
rial disease  cannot  be  detected  with  the  ophthalmoscope. 
Finally,  the  walls  of  the  arteries  may  appear  white  without 
either  opacities  or  hemorrhages  appearing  in  their  distribution. 

The  pathology  probably  corresponds  to  that  of  syphilitic 
disease  of  the  arteries  in  other  parts  of  the  body  (brain,  etc.)  : 
thickening  of  the  intima  and  adventitia,  first  by  cellular,  and 
later  by  fibrous  tissue.  The  thickening  is  often  so  great  that 
the  lumen  of  the  arteries  is  almost  or  quite  obliterated. 


Fig.  36. 


Fig.  37. 


Fig.  37.  Syphilitic  Neuroretinitis  and  Disease  of  the 
Retinal  Arteries,  Fourteen  Days  after  the  Beginning  of  the 
Disease. — The  onset  was  sudden;  one  eye  only  was  affected. 
At  first  there  was  merely  the  picture  of  neuroretinitis  with 
marked  hyperemia  (corresponding  approximately  with  Fig. 
12,  a),  and  in  the  macula  a  diffuse  opacity  with  a  small,  round, 
grayish  patch.  Visiou  was  completely  lost  in  the  center,  in 
the  entire  nasal  half,  and  in  the  upper  outer  portion  of  the 
visual  field.  In  spite  of  immediate  and  energetic  treatment 
vision  did  not  return  and  soon  the  picture  of  Fig.  37  devel- 
oped. Although  no  albumin  was  ever  found  in  the  urine, 
numerous  white  foci  of  degeneration  appeared  in  the  retina 
near  the  macula  and  about  the  optic  disk,  while  the  inferior 
temporal  artery  showed  syphilitic  disease  of  its  walls  in  the 
form  of  small  white  scales.  At  the  same  time  the  neuritis 
disappeared  and  was  replaced  by  atrophy.  Infection  had 
occurred  twenty-seven  years  before. 

This  disease  of  the  retinal  artery,  manifesting  itself  in 
white  scales,  I  consider  peculiarly  characteristic  of  syphilitic 
disease  of  the  vessels. 

This  case  also  shows  that  the  stellate  figure  in  the  macula 
is  not  peculiar  to  albuminuria.  It  is  probably  a  general 
expression  of  intense  disease  of  the  vessels  and  correspond- 
ing interference  with  the  retinal  circulation. 


Fig.  37,  a-  Angioid  Streaks  in  the  Retina. — The  patient, 
aged  fifty,  presents  nothing  important  in  his  clinical  history, 
and  physical  examination  fails  to  demonstrate  the  presence 
of  organic  disease.  One  brother  has  angioid  streaks  very 
similar  to  those  portrayed  in  the  illustration. 

a,  Right  Eye. —  recounting  fingers  at  60  cm.  The  optic 
disk  preserves  its  capillarity  upon  the  nasal  side,  but  presents 
upon  its  temporal  aspect  a  patcli  of  atrophic  color.  It  is  sur- 
rounded by  an  area  of  superficial  choroidal  atrophy.  The 
retinal  vesselsj  both  veins  and  arteries,  are  about  normal  in 
size.  Directly  in  the  macular  region,  and  occupying  a  large 
space  of  the  temporal  half  of  the  eye-ground,  is  a  huge,  almost 
circular  hemorrhage,  broader  and  more  fringed  below,  its 
center  being  occupied  by  whitish  and  yellowish  areas  of 
retinochoroidal  atrophy.  Chiefly  upon  the  nasal  side,  and 
generally  following  the  course  of  the  retinal  vessels  and  lying 
in  the  plane  beneath  them,  is  a  system  of  branching  streaks, 
somewhat  granular  in  appearance,  partly  brownish  and  partly 
reddish  in  color.  Within  the  boundaries  of  the  hemorrhage 
previously  noted  may  be  seen  another  system  of  streaks,  some 
brownish,  and  others  still  fresh  and  hemorrhagic,  and  directly 
connected  with  and  proceeding  from  the  band  of  blood-ex- 
travasation which  circles  this  area.  Downward  and  inward 
from  the  margin  of  the  hemorrhage  may  be  seen  a  small  patch 
of  similar  streaks  just  beginning  to  form.  The  rest  of  the 
eye-ground  is  without  notable  lesion. 

bj  Left  Eye. —  F=  counting  fingers  at  50  cm.  The  optic 
disk  is  round,  the  atrophic  area  being  more  decided  above 
than  elsewhere.  It  is  surrounded  by  a  patch  of  superficial 
choroidal  atrophy  and  pigment  disturbance.  Everywhere 
throughout  the  eye-ground  are  numerous  anastomosing  brown- 
ish and  reddish-brown  streaks,  of  a  character  similar  to  those 
found  in  the  other  eye,  but  evidently  at  a  more  advanced 
period  of  their  formation.  The  macular  region  and  temporal 
half  of  the  eye-ground  are  occupied  by  a  large  vertically  oval 
plaque  of  choroidal  atrophy  streaked  with  black  pigment. 
Bordering  this  below,  and  between  it  and  the  disk  are  broad 
reddish  bands,  somewhat  resembling  exposed  choroidal  ves- 
sels, of  which,  in  some  instances,  they  are  representations. 
It  is  evident  that  the  process  in  the  left,  which  is  the  one  first 
affected,  represents  a  further  advanced  stage  than  that  in  the 
right  eye. 


Fig.  37,  h.  Changes  in  the  Eye-ground  in  Arteriosclerosis  — 
The  left  eye-ground  represented  is  that  of  a  heavily  built  florid 
woman,  aged  sixty-five,  who  since  1890  suffered  much  from 
bronchitis  of  the  influenza  type.  At  night  she  is  somewhat 
asthmatic  and  complains  of  being  rheumatic;  she  is  much 
troubled  with  drowsiness.  The  capillaries  on  her  face  are 
somewhat  distended  over  the  bridge  of  the  nose  and  on  the 
cheek-bones.  The  radial  artery  is  a  little  rigid  to  the  touch, 
and  more  rigid  upon  the  left  than  upon  the  right  side.  The 
temporal  arteries  are  plainly  visible,  although  not  greatly 
distended.  The  urine  has  a  low  specific  gravity  and  contains 
a  trace  of  albumin  and  occasionally  a  hyaline  cast. 

The  vision  of  the  eye  is  f .  Ophthalmoscopically,  the  fol- 
lowing lesions  are  evident :  Edema  of  the  nasal  margin  of  the 
disk  ,  light-colored,  somewhat  tortuous  arteries,  the  upper 
temporal  artery  being  markedly  and  unevenly  narrowed  and 
constricted,  and  bordered  by  one  or  two  old  extravasations ; 
distended  veins,  presenting  numerous  alternate  contractions, 
typically  exhibiting  the  signs  of  mechanic  pressure  where 
they  are  crossed  by  the  diseased  arteries,  the  upper  temporal 
vein  being  so  impeded  in  its  circulation  that  it  is  fringed  with 
a  white  border  of  infiltration,  unevenly  contracted  and  grad- 
ually dwindles  to  a  tortuous  thread,  preceded  by  several 
varicosities ;  in  other  words,  in  one  eye-ground,  al}  of  the 
appearances  which  are  characteristic  of  arterioscLeirosis. 


n^^ 


xaJ^^ 


Fig.  38.  Pigmentary  Degeneration  of  the  Retina  (Retin- 
itis Pigmentosa). — The  disease  always  affects  both  eyes^  The 
degenerative  element  in  the  disease  is  much  more  marked 
than  the  inflammatory,  hence  the  term  pigmentary  degenera- 
tion is  to  be  preferred.  The  degenerative  nature  of  the  dis- 
ease manifests  itself  in  the  contraction  of  the  vessels  which 
appears  very  early  [in  the  disease].  As  the  process  goes  on, 
the  arteries  and  veins  becorae_sn\aller  and  smaller.  At  the 
same  time  the  optic^'nerve  gradually  assumes  a  slightly  atro- 
phic, yellowish-white  appearance.  The  entire  eye-ground  be- 
comes paler,  more  gray  or  leaden-hued,  the  longer  the  disease 
lasts.  The  characteristic  coal-black  pigmented  patches  first 
appear  singly  in  the  periphery  of  the  retina  and  slowly  in- 
crease in  size  as  the  years  go  on.  (The  picture  shows  quite 
an  advanced  stage.)  The  pigment-patches  are  always  small, 
sharply  outlined,  with  serrated  edges  resembling  bone-cor- 
puscles, or  stellate,  and  occasionally  linear  or  bifurcated ; 
they  follow  the  course  of  the  retinjaLjsr^ssels.  The  macular 
region  and  the  region  of  the  optic  nerve  remain  free  from 
pigment-patches  longer  than  any  other  part  of  the  eye-ground. 
White  patches  do  not  occur.  In  exceptional  cases  a  few  yel- 
Towish-white  atrophic  foci  may  later  develop  in  the  choroid, 
usually  very  near  the  periphery,  or  there  may  be  a  sprinkling 
of  whitish  dots  in  the  macular  region.  Later,  sclerosis  of  the 
choroidal  vessels  not  infrequently  becomes  visible,  the  vessels 
assuming  first  a  yellowish,  then  a  whitish  color  (see  Fig.  81). 
The  yellow  coloration  of  the  choroid  vessels  is  seen  above  the 
optic  nerve  in  the  illustration. 


-:-^  :^M^^;; 


> 


Fig.  39. 


Fig.  39.  Pigmentary  Degeneration  of  the  Retina  (Retin- 
itis Pigmentosa),  Advanced  Stage. — The  color  of  the  eye- 
ground  is  more  gray  or  lead-colored,  the  pigment-patches  are 
thicker,  and  in  places  form  a  regular  network.  The  atrophic 
discoloration  of  the  optic  nerve  is  more  marked  and  the  ves- 
sels are  smaller  than  in  the  last  picture.  This  case  illustrates 
the  peculiar  character  of  the  visual  disturbance  in  this  dis- 
ease. The  visual  field  becomes  smaller  and  smaller  and  is 
finally  reduced  to  a  minimum  as  the  disease  progresses.  As 
shown  in  the  figure,  the  outermost  zone  of  the  retina  remains 
free  from  pigmentation  until  this  time.  Accordingly,  the 
defect  in  the  visual  field  was  a  circular  scotoma  correspond- 
ing to  the  zone  of  pigmentation  of  the  retina,  showing  that 
the  retina  loses  its  function  wherever  it  is  attacked  by  the 
disease.  The  pigmentation  is  probably  a  secondary  process, 
as  contraction  of  the  visual  field  may  occur  without  it. 

As  the  disease  progresses  the  pigmentation  spreads  centrifu- 
gally  and  peripheral  vision  is  also  destroyed  ;  while,  on  the  other 
hand,  the  centripetal  advance  of  the  process  causes  contraction 
of  the  central  visual  field. 

The  anatomic  changes  of  the  later  stage  are  shown  in 
Fig.  46,  c  and  d,  where  the  enormous  atroi)hy  of  the  entire 
retina  is  nuich  more  conspicuous  than  in  the  ophthalmoscopic 
image.  The  section  shows  how  the  retina  eventually  becomes 
entirely  converted  into  connective  tissue  and  loses  its  normal 
transparency,  explaining  the  gray  appearance  of  the  eye- 
ground  in  the  severer  forms  of  this  disease. 


Fig.  40.  Disease  of  the  Eye-ground  in  Hereditary  Syphilis. 

— This  figure  and  the  two  following  represent  various  forms 
of  the  same  disease — hereditary  syphilis — which,  like  the 
specific  process  in  general,  manifests  itself  in  various  forms. 
Whether  the  primary  seat  of  the  disease  in  these  cases  is  in 
the  retina  (pigment-epithelium  and  rods  and  cones)  or  in  the 
choroid,  has  not,  in  my  opinion,  been  definitely  established. 
I  have  inserted  these  pictures  among  the  retinal  diseases  be- 
cause the  pigment-patches  appear  to  me  to  be  situated  for  the 
most  part  in  the  retina,  and  because  in  some  cases  the  disease 
shows  a  certain  similarity  to  pigmentary  degeneration  of  the 
retina  which  has  just  been  described.  The  periphery  in  the 
lower  left-hand  portion  of  the  picture  presents  a  leaden  hue 
and  coal-black  circular  and  triangular  pigment-patches.  The 
rest  of  the  eye-ground  is  covered  with  minute  yellow^ish-red 
spots.  The  yellowish-red  roundish  spots  stand  out  from  the 
brown  dotted  background,  which  looks  as  if  it  were  sprinkled 
with  snuflT.  The  retinal  vessels  are  rather  small  and  the  optic 
Inerve  somewhat  discolored.  I  have  chosen  for  this  picture  a 
case  in  which  the  disease  was  very  well  marked.  Sometimes 
;the  sprinkling  is  found  only  in  the  periphery  of  the  eye- 
ground,  and  is  neither  so  well  pronounced  nor  so  extensive  as 
in  this  picture.  But  whenever  this  sprinkling  is  at  all  well 
marked  it  indicates  hereditary  lues.  A  similar  but  much 
finer  sprinkling  of  the  eye-ground  occurs  in  cases  of  insuf- 
ficient pigmentation  (in  blondes).  The  latter,  however,  is,  as 
a  rule,  seen  only  by  the  direct  method,  while  the  luetic  can  be 
seen  by  the  indirect  method. 


Fig.  41.  Alterations  of  the  Eye-ground  in  Congenital 
Syphilis. — In  this  form,  which  is  not  quite  so  severe  as  that 
shown  in  the  last  picture,  the  disease  is  often  confined  for  a 
long  time  to  the  periphery.  In  this  disease  also  the  pigment- 
patches  are  probably,  for  the  most  part,  situated  in  the  retina 
and  are  caused  by  a  disease  of  the  pigment-epithelium.  I  am 
unable  to  decide  whether  the  pale  linear  and  circular  yellow- 
ish patches  are  situated  in  the  choroid  or  in  the  pigment- 
epithelium.     They  may  be  situated  in  one  or  the  other. 

This  and  the  following  form  of  the  disease  are  not  rarely 
found  after  a  diffuse  interstitial  keratitis  if,  after  the  cornea 
has  become  sufficiently  cleared  up,  the  periphery  of  the  eye- 
ground  is  carefully  examined.  In  some  cases  the  patches 
may  be  confined  to  one  side,  in  others  they  may  be  scattered 
more  or  less  over  the  entire  eye-ground  [and  on  both  sides]. 

In  the  case  here  represented  there  had  been  a  keratitis. 

The  increased  pigmentation  at  the  margin  of  the  optic  disk, 
seen  in  Figs.  40-42,  may  not  be  present  even  when  there  is  a 
chorioretinitis,  and  Antonellis's  supposition  that  this  marginal 
pigmentation  (choroidal  ring)  is  a  stigma  of  hereditary  syph- 
ilis is  not  quite  correct.     It  occurs  also  in  normal  eyes. 


Fig.  42.  Alteration  of  the  Eye-ground  in  Congenital  Syph- 
ilis.— In  place  of  the  black  and  gray  patches,  which  predom- 
inate both  in  size  and  number  in  the  foregoing  picture,  we 
find  in  some  cases  only  whitish,  also  circular,  and  often  con- 
fluent patches.  The  larger  of  these  are  undoubtedly  situated 
in  the  choroid.  This  is  shown  in  the  figure  by  the  oval  white 
patch  traversed  by  a  red  vessel.  It  is  a  choroidal  vessel, 
hence  the  choroidal  tissue  near  the  vessel  is  absent  and  the 
white  of  the  sclera  shows  through.  There  is  no  doubt,  how- 
ever, that  the  pigment-epithelium  of  the  retina  has  disap- 
peared at  the  site  of  the  patches,  and  is  slightly  increased 
about  their  margins,  so  that  the  margins  appear  somewhat 
darker  than  the  surrounding  tissue.  This  condition  also 
followed  an  attack  of  parenchymatous  keratitis. 

Occasionally  the  forms  shown  in  Figs.  41  and  42  are  asso- 
ciated, resulting  in  a  mixture  of  both  dark  and  light  circular 
confluent  patches  at  the  periphery,  while  sometimes,  in  addi- 
tion, we  find  the  form  shown  in  Fig.  40— viz.,  minute  red  and 
yellow  spots  on  a  brown,  mottled  background,  with  a  sprink- 
ling of  small  pigment-patches. 

In  general,  these  three  types  of  hereditary  specific  eye- 
ground  disease  show  a  tendency  to  the  formation  of  spherical 
foci,  which  coalesce  and  form  irregular  figures. 


Fig.  43. 


Fig.  43.  Secondary  Pigmentation  of  the  Retina  in  Dis- 
seminated Choroiditis. — In  the  central  portion  the  picture 
somewhat  resembles  pigmentary  degeneration  (Figs.  38  and 
39).  The  optic  nerve  is  somewhat  pale,  the  vessels  are  small, 
the  eye-ground  lighter  than  normal,  with  a  suggestion  of  yel- 
lowish-gray. This  area  also  contains  pigment-patches  exactly- 
resembling  those  seen  in  pigmentary  degeneration.  In  addi- 
tion, however,  there  are  large  white  circular,  sharply  outlined 
patches  near  the  periphery.  They  correspond  to  portions  of 
the  sclera  which  have  become  visible,  because  both  the  pig- 
ment-epithelium of  the  retina  and,  owing  to  the  disseminated 
foci  of  inflammation  in  the  choroid — choroiditis  disseminata — 
the  choroidal  tissues  have  disappeared-  Nothing  remains  of 
the  latter  except  here  and  there  a  few  isolated  choroidal  ves- 
sels, traversing  the  patches  like  narrow  red  ribbons.  And 
even  the  vessels  are  wanting  in  many  of  these  atrophic  foci 
of  the  choroid.  One  of  them  contains  at  its  center  a  small 
patch  of  pigment.  This  variety  of  chorioretinitis,  a  later 
stage  of  which  is  here  represented,  is  often  complicated  with 
more  or  less  opacity  of  the  vitreous,  and  is  frequently  caused 
by  syphilis. 

Secondary  pigmentation  of  the  retina  also  occurs  after 
other  forms  of  choroiditis  if  the  inflammation  is  severe  and 
lasts  a  long  time,  as  will  be  shown  in  some  of  the  later 
pictures. 


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Fig.  45. 


Fig.  45.  Disease  of  the  Macula  Lutea  of  the  Retina 
resulting  from  a  High  Grade  of  Myopia. — At  a  one  sees  the 
reddening  and  slight  swelling  of  the  nasal  portion  of  the 
nerve  that  are  apt  to  develop  when  eyes  of  this  kind  are 
subjected  to  strain,  and  which  probably  represent  a  func- 
tional hyperemia,  although  they  are  regarded  by  some  as 
inflammatory  conditions.  The  disk  also  is  somewhat  oblique 
and  surrounded  by  an  atrophied  portion  of  the  choroid  in  the 
form  of  a  "  meniscus  "  or  cone.  The  pigmentation  of  the  eye- 
ground  is  somewhat  ftiinter  than  normal.  The  macular  dis- 
ease manifests  itself  in  yellowish-red  spots  and  a  somewhat 
irregular  pigmentation.  The  middle  of  the  fovea  is  occupied 
by  a  black  spot  surrounded  by  small  hemorrhages. 

Fig.  45,  h,  represents  a  more  advanced  stage  of  the  disease, 
recognized  by  an  increase  in  the  pigmentation  and  the  pres- 
ence of  white  spots,  which  indicate  that  the  choroid  is  involved 
and  atrophied  in  places,  exposing  the  sclera.  A  few  pale 
spots  extend  as  far  as  the  atrophic  meniscus  about  the  optic 
nerve. 

Fig.  45,  c,  shows  an  advanced  case  of  macular  disease,  in 
which  there  is  not  the  slightest  doubt  of  the  choroid  being 
involved.  The  optic  nerve  is  surrounded  by  an  atrophic  ring 
which  is  broadest  on  the  side  near  the  macula.  The  macular 
region  is  occupied  by  a  large  white  patch  with  sinuous  and 
partly  pigmented  outlines  within  which  the  choroid  has 
entirely  disappeared,  except  for  a  few  vessels  and  traces 
of  pigment.  To  the  temporal  side  of  this  the  choroid  and 
retina  have  disappeared,  leaving  a  large  atrophic  patch 
extending  as  far  as  the  equator,  covered  with  irregular 
masses  of  pigment. 


Fig.  46.  a.  Secondary  Pigmentation  of  tlie  Retina  caused 
by  a  Fragment  of  Percussion-cap  (not  shown  in  the  picture), 
which  remained  in  the  eye  twenty  years. — Posterior  segment 
of  the  eye  seen  from  the  frout.  At  the  center  one  sees  the 
optic  nerve  and  the  retinal  vessels  radiating  in  all  directions. 
In  the  left  half  of  the  figure  the  retina  is  detached  from  its 
base,  but  whether  this  condition  was  present  during  the  indi- 
vidual's life,  or  is  an  artificial  product,  cannot  be  determined. 
The  area  of  retinal  detachment  shows  the  pigmentation  which 
closely  resembles  that  seen  in  pigmentary  degeneration  (retin- 
itis pigmentosa,  see  Figs.  38  and  3D)  better  than  the  rest  of 
the  eye-ground.  This  preparation  shows  more  advanced 
changes  in  the  retina  than  are  seen  in  the  ophthalmoscopic 
picture  in  Fig.  74,  which  also  shows  the  changes  produced  in 
the  eye  by  a  piece  of  percussion-cap.  The  patient,  who  was 
recently  examined,  now  shows  much  more  marked  pigmenta- 
tion of  the  retina  than  at  the  time  this  picture  was  taken. 

Fig.  46,  h.  Sagittal  Section  of  an  Eye  with  a  Total  or 
Funnel-shaped  Retinal  Detachment  of  Long  Standing. — The 
retina  extends  forward  in  the  form  of  a  band,  which  is  broader 
in  front,  still  contains  some  remains  of  the  degenerated  vit- 
reous body,  and  surrounds  the  lens.  The  interval  between 
the  retina  and  the  choroid  is  occupied  by  an  amorphous 
exudate. 

Fig.  46,  c.  Pigmentary  Degeneration  of  the  Retina  (Retin- 
itis Pigmentosa). — This  picture  represents  an  advanced  stage 
of  the  disease,  hence  the  normal  structure  of  the  retina  is 
entirely  lost,  being  represented  by  a  fibrous  membrane  con- 
taining many  nuclei  interspersed  with  pigment.  The  rods  and 
cones  have  disappeared  completely.     The  choroid  is  normal. 

Magnified  30  times. 

Fig.  46,  d.  A  Portion  of  the  Same  Specimen  under  a  Higher 
Power. — In  places  the  pigment  is  collected  about  the  blood- 
vessels in  accordance  with  what  we  see  in  the  ophthalmoscopic 
image :  P.P.,  pigment  in  the  retina. 

Magnified  78  times. 


Retina 


Nero,  optic. 


^L        b 


Chop. 


Retina  Corpus  vitreum  Retina. 


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Fig.  49. 


Fig.  49.  Perforation  of  the  Macula  Lutea  after  Contu- 
sion of  the  Eveball.^— -The  patient,  a  man  of  fifty-two,  had 
had  a  stick^rown^  liis  left  eye  ten  years  before.''  Since 
that  time  the  vision  of  the  injured  eye  was  impaired,  and  at 
the  time  of  my  first  examination,  when  the  picture  of  the 
eye-ground  was  made  (1891),  he  could  only  count  fingers  at 
a  distance  of  1.5  meters.  At  the  center  of  the  macula  there ^ 
is  a  circular  opening  with  sharply  defined  edges  about  half 
the  size  of  a  papilla,  the  surrounding  area  is  slightly  opaque 
with  minute  dots  and  in  places  covered  with  pale  glistening 
spots  and  patches.  Of  the  latter  a  few  are  also  found  in  the 
retinal  defect  characterized  by  its  red  color.  The  floor  of  this 
defect  is  almost  uniformly  red  and  by  the  direct  method  shows 
only  a  very  fiiint  mottling,  representing  the  mosaic  arrangement 
of  the  pigment-epithelium.  But  this  can  only  be  recognized 
with  great  difficulty.     The  rest  of  the  eye-ground  is  normal. 

I  have  frequently  seen  defects  of  this  kind  after  severe 
contusion  of  the  eyeball  by  a  blow  with  a  stick  or  fist,  explo- 
sions, arrow  wounds,  stones,  etc.  The  opening  is^sually  cir- 
cular, but  may  also  become  ovai)in  outline,  owing  to  shrinking 
and  consequent  deterioration  of  the  retina  in  the  neighborhood 
of  the  macula.  It  is  probable  that  openings  of  this  kind  in 
the  fovea  may  appear  spontaneously  in  advanced  age  without 
any  traumatism,  possibly  owing  to  arteriosclerosis.  In  a  case 
of  this  kind  I  saw  such  a  perforation  in  both  eyes  in  a  woman 
sixty-four  years  of  age,  with  marked  arteriosclerosis  and  some 
albuminuria.  (The  Editor  has  reported  similar  cases  and  one 
similar  lesion  which  appeared  after  non-traumatic  iridocyclitis.) 

1  See  Haab,  Die  traiimatische  Durchl'dchening  der  Makula  lutea.  Ztschr. 
fur  Augenheilk.,  1900,  p.  113. 

2  Case  II.  in  the  article  just  cited. 


Fig.  50,  a.  Section  through  the  Macula  Lutea  and  Sur- 
roundings in  Macular  Disease  resulting  from  Orbital  Tumor. 

— The  specimen  was  taken  from  the  eyeball  shown  in  Fig.  54,  a, 
after  enucleation.  The  yellowish-red  patch  with  slightly  pig- 
mented borders  seen  in  that  figure  is  represented  in  the  trans- 
verse section  by  a  separation  of  the  pigment-epithelium  in  the 
region  of  the  fovea  centralis,  where  the  epithelium  is  without 
pigment  in  places  or  is  altogether  wanting.  The  cones  and 
corresponding  nuclei  are  also  wanting  in  considerable  areas. 
The  nerve-fiber  and  ganglion-cell  layers  also  show  a  marked 
alteration.  In  the  ganglion-cell  layer  the  diminution  of  the 
cells  and  vacuole-formation  at  once  become  apparent  (cf. 
Fig.  14,  c,  of  the  normal  macula,  which  is  represented  under 
the  same  power).  The  choroid  does  not  show  any  marked 
changes. 

Magnified  30  times. 

Fig.  50.  h  and  c.  Transverse  Sections  through  the  Retina 
in  Thrombosis  of  the  Vena  Centralis  Retinae  (cf  Fig.  33,  6). 
— Section  b  corresponds  to  the  neighborhood  of  the  papilla ; 
section  c,  to  an  area  somewhat  more  remote.  Hence  we  see 
in  6  a  larger  and  more  engorged  retinal  vein  (^Ret  F.),  while 
c  shows  a  greater  number  of  small  vessels  more  or  less 
engorged  by  the  damming  back  of  the  blood.  In  addition 
there  are  numerous  hemorrhages  of  varying  sizes  scattered 
throughout  the  entire  preparation.  In  c  many  vacuoles  and 
fissures  appear  in  the  tissue  which  must  be  referred  to  edema. 

1,  Nerve-fiber  and  ganglion-cell  layer;  3,  inner  nuclear 
layer ;  ^,  internuclear  (outer  reticular)  layer ;  5,  outer  nuclear 
layer ;  6,  layer  of  rods  and  cones. 

Sections  h  and  c  magnified  90  times. 


Retina 


Corp.  vitr. 

Fov.  central. 


a 


Retina 


•■V^vJ?*^"— ""  '■^'•'^ 


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Fig.  50. 


Fig.  51.  Opacity  of  the  Eetina  due  to  a  Blow  on  the  Eye ; 
Berlin's  Opacity;  Commotio  Retinae  (direct  method,  reduced). 
— This  form  of  opacity  of  the  retina,  which  is  often  observed 
after  external  violence  to  the  eye  by  a  blunt  instrument,  was 
first  described  and  studied  by  Berlin.  The  changes  soon  pass 
off,  so  that  they  are  best  seen  immediately  after  the  receipt  of 
the  injury.  The  opacity  is  often  produced  by  a  blow  with  a 
fist  or  stick,  by  striking  the  eye  forcibly  against  a  hard  object, 
a  blow  from  a  stone  or  snowball,  etc.  A  milkish  white  opacity 
is  often  seen  in  two  separate  portions  of  the  retina,  one  at  the 
place  where  the  eye  was  struck  and  another  more  or  less 
extensive  area  in  the  region  of  the  macula  lutea.  The  former 
is,  as  a  rule,  more  extensive,  more  marked,  and  more  per- 
sistent, while  that  in  the  macular  region  is  less  intense  and  v  O-  i 
disappears  more  rapidly.  The  macula  and  visual  power  ^ 
remain  intact.  The  opacity  at  the  periphery  does  not,  as  a 
rule,  obscure  the  retinal  vessels.  The  condition  has  undoubt-^  ^"^ 
edly  often  been  mistaken  for  separation  of  the  retina.  The 
nature  of  the  opacity  is  not  as  yet  well  understood.  The  pres- 
ent picture  was  taken  a  few  hours  after  the  patient  had  been 
hit  in  the  eye  with  a  snowball. 


Fig.  52.  Opacity  of  the  Retina  due  to  a  Blow  on  the  Eye ; 
Berlin's  Opacity;  Commotio  Retinae. — In  this  case  the  contu- 
sion was  much  more  severe,  the  eye  having  been  struck  by  a 
large  piece  of  iron ;  the  retinal  opacity  is,  accordingly,  more 
marked,  and  there  are  even  a  few  small  hemorrhages  in  the 
opaque  area  which  corresponds  to  the  site  of  the  direct  in- 
jury (the  upper  border  of  the  picture,  hence  the  lower  portion 
of  the  retina).  The  abnormal  appearances  all  disappeared  in 
a  few  days,  the  opacity  in  the  macular  region  first,  and  soon 
afterward  that  in  the  lower  part  of  the  retina.  This  traumatic 
opacity  is  readily  distinguished  from  separation  of  the  retina. 
Aside  from  the  fact  that  a  very  recent  detachment  of  the 
retina  is  usually  more  transparent  instead  of  milky  white,  the 
■course  of  the  vessels  in  commotio  retinae  is  not  affected  ;  there 
is  no  parallactic  dislocation  or  marked  degree  of  hyper- 
metropia.  Besides,  ^^^fjfel^"  of  a  retinal  detachment  are 
wanting. 

It  is  interesting  to  note  that  in  these  cases  there  is  sometimes 
found  at  the  center  of  the  fovea  an  isolated,  more  or  less  well- 
marked  pale  spot,  distinctly  separated  from  the  remainder  of 
the  macular  opacity.  This  is  probably  not  caused  by  opacity 
of  the  retina  because  the  membrane  is  exceedingly  thin  at  this 
point ;  it  is  probable  that  its  substratum  is  situated  behind 
the  floor  of  the  central  fovea,  perhaps  in  the  pigmentary  epi- 
thelium, perhaps  between  the  latter  and  the  layer  of  rods  and 
cones.     The  phenomena  is  also  transitory. 


Fig.  52. 


Fig.  53. 


Fig.  53.  Disease  of  the  Macula  Lutea  due  to  the  Presence 
of  a  Foreign  Body  in  the  Vitreous. — Such  is  the  sensitiveness 
of  the  macula  lutea  that  even  aseptic  bodies  that  have  pene- 
trated into  the  deeper  layers  of  the  eye  often  produce,  after 
a  short  time,  an  isolated  disease  of  this  portion  of  the  retina 
without  directly  injuring  the  macula.  Fig.  53  shows  four 
examples  of  this  kind :  The  small  grayish  white  spots  at  the 
center  of  the  macula  seen  in  a  were  produced  by  a  particle 
of  a  copper  shell,  which  remained  five  days  in  the  vitreous 
body.  The  spots  disappeared  completely  after  the  splinter 
was  removed,  and  two  and  a  half  months  later  vision  was 
entirely  restored. 

b  shows  a  yellow  discoloration  of  the  macular  region  a  year 
after  a  particle  of  copper  (from  a  cap)  entered  the  anterior 
portion  of  the  eye.  The  foreign  body  was  not  removed  and 
produced  the  changes  shown  in  Fig.  74,  which  represents  a 
later  stage.  Eventually  the  discoloration  decreased,  and  at 
the  present  time  of  writing,  seventeen  years  after  the  injury 
was  sustained,  vision  is  still  i.  This,  however,  is  an  excep- 
tional case. 

The  round  grayish  spot  shown  in  c  was  produced  by  a  steel 
splinter  that  remained  in  the  retina  twenty  hours.  The 
splinter  which  is  shown  in  Fig.  55,  a,  was  drawn  back  into 
the  anterior  portion  of  the  eye  by  means  of  a  large  magnet 
and  thus  removed.  The  center  of  the  macula  at  first  showed 
a  yellowish  pigmentation  which  was  gradually  replaced  by 
the  dark  spot  seen  in  the  picture,  painted  three  months  after 
the  injury  was  sustained.  As  a  consequence,  vision  was  re- 
duced to  Y^^,  the  condition  of  the  eye  in  other  respects  not 
being  impaired. 

The  delicate  pigmentation  shown  in  d  is  owing  to  the  pres- 
ence of  an  iron  splinter  from  a  hook  in  the  vitreous,  which 
remained  a  week  and  was  then  removed  by  means  of  a  small 
magnet.     Vision  was  reduced  to  |. 


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Fig.  56.  Air-bubble  in  the  Upper  Portion  of  the  Vitre- 
ous due  to  tlie  entrance  of  an  iron  splinter  (direct  method, 
reduced). — The  accident  occurred  shortly  before  the  picture 
was  made,  while  the  patient  was  working  with  iron,  and  the 
splinter  became  embedded  in  the  lower  part  of  the  retina. 
Its  entrance  was  followed  by  the  formation  of  an  air-bubble 
which  disappeared  after  a  few  hours.  These  air-bubbles 
always  disappear  very  rapidly,  so  that  they  can  only  be  seen 
immediately  after  the  injury.  Several  air-bubbles  of  this  kind 
may  be  found  in  the  vitreous  body  after  the  entrance  of  a 
splinter.  Hence  air  in  the  vitreous  is  an  important  diagnostic 
point,  indicating  a  foreign  body  in  the  eyeball.  Occasionally, 
although  rarely,  the  mere  injury  of  the  eye  by  a  splinter 
may,  without  its  remaining  in  the  eye,  be  followed  by  the 
entrance  of  air  into  the  vitreous,  so  that  the  finding  of  such 
an  air-bubble  does  not  positively  indicate  the  presence  of  a 
splinter  in  the  eye. 

Air-bubbles  in  the  vitreous  look  like  air-bubbles  in  a 
microscopic  section. 

In  this  case  the  splinter  was  immediately  removed  by 
means  of  the  author's  large  magnet,  whereupon  the  wound 
rapidly  healed  and  vision  was  completely  restored. 

For  further  details  about  my  method  of  operating  with  the 
magnet,  the  reader  is  referred  to  Haab's  Atlas  and  Epitome  of 
Operative  Ophthalmology. 


Fig.  56. 


Fig.  57. 


Fig.  57.  Old  Injury  of  the  Retina  by  an  Iron  Splinter.— 

In  the  two  cases  shown  in  the  foregoing  figure,  the  foreign 
bodies  had  been  only  a  short  time  in  the  retina  and  either 
lay  apparent  on  the  surface  or  were  embedded  within  the 
membrane ;  the  present  figure  shows  two  cases  in  which  the 
splinters  had  penetrated  the  eye  some  time  before  and  now 
present  a  somewhat  diflTerent  picture.  The  foreign  bodies  are 
here  covered  by  a  whitish  exudate,  the  black  color  of  the 
metal  showing  only  in  two  places  in  a.  In  the  latter  the 
splinter,  which  had  been  almost  two  months  in  the  retina, 
produced  a  characteristic  alteration  in  the  immediate  neigh- 
borhood. The  pigment-epithelium  has  in  part  disappeared 
and  the  splinter  is  surrounded  by  a  light  colored  areola  in 
which  a  few  choroidal  vessels  are  seen.  This  areola  also 
shows  an  irregular  pigmentation,  which  becomes  more  intense 
near  the  foreign  body.  In  the  adjacent  region  there  are  three 
small  choroiditic  foci,  light  in  color,  with  ill-defined  edges, 
and  surrounded  by  irregular  pigmentation. 

In  b  there  are  no  changes  in  the^  immediate  surrounding 
of  the  splinter,  although  at  the  time  the  picture  was  made 
the  splinter  had  been  in  the  retina  six  weeks.  (For  further 
details  concerning  this  case,  see  Hiirzeler,  loc.  city  B,  case  4.) 


'^ 


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.S-J-g^^-2  »  5»«i5  A         °  5-2  « 

Ci_i  '^Oojf-i^rOO'^a:  53    vr_-  i,    a:)        ' 


Fig.  58.1. 


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4-1       CD  ft>  ^  tf  (^  t3-^^  n>        g  S-^  o  e  2        e  o  a> 


»-<  CD 


Fig.  59.  Retinal  Detachment  in  the  Temporal  Portion  of 
the  Eye-ground. — Although  the  injury  is  one  of  about  twelve 
weeks'  standing,  it  may  be  called  a  recent  injury,  as  there 
is  not  as  yet  any  marked  degree  of  opacity  or  wrinkling 
of  the  retina.  The  picture  of  the  retinal  detachment  shows 
one  important  phenomenon,  namely,  the  absence  of  the 
roidal  striations  in^jiL&^-detai^hed  -fti'ear''ttTe  striations  being 
obscured  by  tlie  slight  opacity  of  the  retina,  as  also  by  the 
subretinal  fluid.  In  the  marginal  zone  of  the  macula,  where 
the  retina  is  thickest,  the  opacity  is  most  marked,  so  that  the 
central  depression,  which  is  the  thinnest  portion,  appears  more 
fright  red  by  mn||-nj;t.-  on  the  other  hand,  the  red  color 

^//^  01  tne  choroid  shines  through  more  distinctly  than  in  other 
kinds  of  macular  opacities,  because  the  retina  is  thin  in  the 

1   '^    region  of  the  fovea  on  account  of  the  atrophy  of  its  elements. 

^^^^"^"^ Occasionally,  after  the  retinal  detachment  has  lasted  for  some 
time,  an  actual  perforation  may  even  be  observed  in  the  center 
of  the  fovea. 

The  detachment,  which  in  this  case  occupies  the  temporal 
quadrant  of  the  eye-ground,  is  quite  superficial — that  is  to 
say,  not  very  far  removed  from  the  choroid.  In  the  macular 
region  there  is  an  hypermetropia  of  4.0  D  ;  toward  the  periph- 
ery the  hypermetropia  is  7  to  8.0  D,  while  at  the  papilla  the 
eye  is  emmetropic.  Vision  is  reduced  to  power  of  counting 
the  fingers  at  a  distance  of  3  meters. 


Fig.  60. 


Fig.  60.  Retinal  Bands  and  Retinal  Detachment  after  a 
Punctured  Wound  of  the  Eye. — Four  years  after  an  insig- 
nificant injury  of  the  eye  from  a  sharp  piece  of  tin,  which  had 
pierced  the  sclera  to  the  temporal  side  of  the  cornea,  vision 
began  to  deteriorate.  As  the  picture  shows,  there  was  a 
grayish-white  exudate,  spherical  in  shape,  in  the  outer  and 
upper  portion  between  the  corneal  border  and  the  equator, 
projecting  some  distance  into  the  vitreous,  seen  in  the  picture 
at  the  left  lower  border.  Below  this  exudate,  which  occu- 
pied the  site  of  the  puncture  (and  touching  it  above  in  the 
picture),  the  retina  was  detached,  and  this  detachment  ex- 
tends some  distance  along  the  upper  border.  Wherever  the 
retina  is  detached  the  color  is  paler,  and  we  see  folds  and 
irregular  tortuous  vessels  somewhat  darker  in  color  than  the 
other  vessels  in  the  picture.  Between  the  detachment  (in 
the  lower  portion  of  the  eye)  and  the  exudate  are  a  number 
of  white  bands  or  lines,  some  of  which  anastomose,  although 
in  the  main  they  run  in  the  same  general  direction.  In  the 
portion  occupied  by  these  lines  there  is  no  retinal  detachment. 
I  am  unable  to  determine  whether  these  bands  are  of  the 
same  character  as  those  shown  in  Fig.  58,  b.  For  weeks  they 
showed  no  change.  The  macular  region  presented  abnor- 
mally heavy,  somewhat  irregular  pigmentation.  The  retinal 
detachment  is  likely  to  increase  as  time  goes  on. 


Fig.  61.  Retinal  Detachment  at  the  Inner  Upper  and 
Inner  Lower  Portion  of  the  Right  Eye  (indirect  method). — 
At  the  inner  upper  portion  there  is  a  slight  tear  in  the 
detachment  through  which  the  red  color  of  the  choroid  is 
seen.  Toward  the  nasal  side  there  is  a  strip  of  retina  that 
has  not  yet  become  detached.  Above  and  below  this  strip 
the  detachment  is  quite  marked  (the  detachment  became  even 
greater  later  on,  in  spite  of  treatment). 

In  this  case  the  detachment  which  had  existed  for  three 
months  appeared  quite  suddenly.  Both  eyes  had  been  oper- 
ated on  thirty-five  years  before  for  lamellar  or  congenital 
cataract ;  in  the  left  eye  the  pupil  was  cloudy,  but  the  right 
eye  had  fairly  good  vision  up  to  the  present  time  in  spite  of 
the  aphakia.  From  the  presence  of  a  fine  band  in  the  ante- 
rior portion  of  the  vitreous,  wliich  otherwise  is  quite  clear, 
it  may  be  suspected  that  an  injury  of  the  vitreous  with  pro- 
lapse occurred  at  the  time  of  the  operation. 

This  case  shows  excellently  the  great  danger  of  injury 
of  the  vitreous,  and  that  the  retinal  detachment  which  it 
produces  may,  under  certain  circumstances,  be  greatly  delayed 
— in  this  case  thirty-five  years. 


Fig.  62. 


Fig.  62.  Retinal  Detachment  fSolutio  Retinae)  with 
Laceration. — It  is  not  uncommon  to  find  in  retinal  detach- 
ments a  tear  or  hole  of  varying  size  and  shape  in  the  detached 
portion  of  the  retina.  The  opening  is  quite  often  surrounded 
by  a  shred  of  the  membrane  of  a  corresponding  outline,  which 
appears  to  have  been  torn  out,  and  then  reflected  or  puckered. 
In  the  present  case  the  tongue-shaped  i)ortion  of  retina  ex- 
tending from  the  lower  margin  of  the  picture  toward  the  red, 
approximately  quadrangular  opening,  in  the  detached  portion 
of  which  it  forms  the  lower  border,  was  probably  torn  out  of 
the  detachment,  and  thus  produced  the  opening.  According 
to  Leber,  the  vitreous  as  it  shrinks  strips  the  retina  from  the 
pigment-epithelium  and  occasionally  produces  an  opening  cor- 
responding to  a  spot  where  it  is  more  firmly  attached  to  the 
retina.  Through  the  opening,  the  edges  of  which  are  some- 
what reflected,  we  see  the  choroid  with  its  vascular  striation, 
which  is  very  pronounced  above,  where  the  retina  is  normal  and 
transparent.  Toward  the  left  in  the  picture  the  detachment 
is  beginning  to  spread.  At  this  point  it  is  quite  superficial. 
The  optic  nerve  is  invisible,  being  behind  the  retinal  detach- 
ment. 


Fig.  63.  Hemorrhagic  Retinitis  of  Pregnancy. — In  spite 
of  the  presence  of  the  stellate  figure  in  the  macular  region, 
no  albumin  was  found  in  repeated  examinations  of  the  urine. 
After  the  woman's  delivery  at  term,  the  disease,  which  affected 
the  left  eye,  subsided  spontaneously  within  three  weeks.  The 
entire  mass  of  hemorrhages  and  white  degenerated  patches 
seen  in  the  picture  disappeared  completely,  although  the 
woman  was  extremely  anemic  both  before  and  after  her 
delivery.  Vision  also  was  completely  restored.  The  right 
eye  was  not  affected.  It  may  be  that  we  have  to  deal  with 
an  incomplete  thrombosis  of  the  central  vein,  which  only 
partially  occluded  the  lumen  of  the  vessel. 


» ; 


^   > 


77  ,fJ'\,''.\ 


Fig.  64.  Retinitis  Circinata  (recently  described  and  named 
by  Fuchs),  seen  in  the  right  eye  of  an  otherwise  healthy  man 
seventy-seven  years  of  age,  whose  other  eye  was  normal. — 
A  number  of  isolated  and  coalescent,  glistening  white  patches, 
closely  resembling  in  color  those  seen  in  albuminuric  retinitis 
and  diabetes,  are  grouped  about  the  macula  in  the  form  of  an 
oval.  At  the  broadest  portion  of  this  girdle  surrounding  the 
macula  are  a  number  of  isolated  whitish  patches  and  dots, 
some  of  which  resemble  crystals.  Here  and  there  within  or 
among  the  white  patches  are  small  round  hemorrhages.  The 
[white  patches  are  traversed  by  the  retinal  vessels,  which 
lusually  do  not  show  any  changes  in  the  ophthalmoscopic 
image  in  this  disease. 

The  macular  region  is  slightly  opaque  and  the  foveal  reflex 
is  absent.  As  vision  is  only  one-fiftieth,  it  may  be  assumed 
that  marked  signs  of  macular  disease  would  otherwise  appear 
in  the  microscopic  image.  A  little  to  one  side  of  the  center 
of  the  fovea  are  a  few  pale  patches  and  one  dark  spot  which 
occupies  the  pigment-epithelium.  In  other  cases  marked 
changes  were  observed  in  the  macular  region,  consisting  of 
yellowish-gray  or  yellow,  irregular,  washed-out  patches. 

The  rest  of  the  eye-ground  is  normal.  At  the  temporal 
border  of  the  papilla  there  is  a  narrow  sickle,  although  there 
is  no  myopia. 


Fig.  65.  Changes  in  the  Eye-ground  in  Leukemia. — The 
case  is  one  of  splenomedullary  leukemia  with  enormous 
splenic  enlargement  in  a  young  patient  of  Prof.  Eichhorst. 
The  disease  began  about  a  year  and  a  half  ago.  The 
patient  does  not  as  yet  complain  of  any  visual  impairment. 
Although  the  number  of  leukocytes  is  greatly  augmented, 
the  eye-ground  is  not  paler  than  normal ;  in  fact,  there 
are  at  the  periphery  a  number  of  darker  patches  due  to 
increased  pigmentation.  The  most  conspicuous  feature  is 
that  the  arteries  and  veius  of  the  retina  have  the  same  color- 
ing, the  veins  being  only  recognized  by  their  tortuosity,  which 
is  excessive,  and  their  increased  diameter.  The  color  of  the 
retinal  vessels  is  almost  white,  this  being  due  in  part,  no 
doubt,  to  the  pale  color  of  the  blood,  but  more  particularly 
to  changes  in  the  vessel-walls,  especially  at  the  periphery, 
where  we  observe  minute  light  and  dark  dots  and  a  few 
larger  pale  patches ;  also  two  hemorrhages  with  pale  centers. 
Round  the  optic  nerve  and  the  macula  the  retina  is  slightly 
opaque.  The  papilla  is  cloudy  and  paler  than  normal  and 
its  outlines  are  obscured.  The  changes  are  about  equally 
marked  in  both  eyes. 


Fig.  66.  Glioma  of  the  Retina. — The  picture  was  taken 
from  a  boy  two  and  a  half  years  of  age,  who  came  to  me 
with  advanced  gliomatous  proliferation  in  the  left  eye.  A 
careful  examination  of  the  right  eye  revealed  in  the  nasal 
portion  of  the  eye-ground  a  small  glioma,  appearing  as  an 
oval  grayish  nodule  with  a  rounded  thou^h^omewhat  irreg- 
ular surface.  The  growth  was  sharply^^tlined  and  the 
surrounding  tissues  showed  no  changes.  The  rest  of  the  eye- 
ground  was  quite  normal,  the  pigmentation  is  not  marked, 
and  the  choroidal  vessels  are  plainly  seen.  Although  this 
nodule  grew  very  slowly,  the  neoplasm  in  the  other  eye  prob- 
ably spread  to  the  brain,  so  that  death  ensued  at  the  age  of 
three  and  a  half  years. 


Fig.  67,  a,  explains  the  ophthalmoscopic  picture  of  the 
Retina  in  Pernicious  Anemia  portrayed  in  Fig.  31. — The 
figure  shows  a  small  portion  of  the  retina  in  transverse  sec- 
tion containing  the  hemorrhages  colored  a  bright  red  with 
eosin,  especially  in  the  anterior  layers  of  the  retina.  They 
are  especially  plentiful  round  the  blood-vessel  F,  where  there 
is  also  a  slight  hemorrhage  in  the  internuclear  (outer  reticular) 
layer. 

Magnified  90  times. 

Fig.  67,  h.  Small  Inflammatory  Focus  in  Disseminated 
Choroiditis  (superficial  view). — The  choroidal  vessels  seen  in 
Fig.  70  do  not  appear  in  this  picture.  On  the  other  hand, 
owing  to  the  high  power,  the  variegated  form  of  the  pigment- 
cells  of  the  choroid  and  the  nuclei  of  the  cells  which  compose 
the  infiltrate  can  be  made  out.  The  picture  was  taken  from 
a  thin  longitudinal  section  of  the  choroid. 

Magnified  112  times. 


Corpus   Ditreum 
Haemorrhag.        ^ 


Chorioidea 


a 

Haemorrhag . 

:V--.-.««||^,^,...    I 


\1^      V,--." 


Fig.  67. 


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i         9 


4- 


l-C 


Fig.  68. 


DISEASES  OF  THE  CHOROID. 

(Figs.  68-86.) 

Fig.  68.  Recent  Disseminated  Choroiditis.— Inflammatory 
foci  in  the  choroid  are  recognized  in  the  main  by  the  fact 
that  they  are  traversed  by  the  retinal  vessels.  In  the  early 
stages  they  appear  either  yellowish-white  or  grayish-white 
with  ill-defined  outlines.  The  condition  is  soon  complicated 
by  changes  in  the  pigment  and  the  margins  of  the  foci 
become  dark,  or  else  the  center  appears  more  deeply  colored. 
In  addition  to  the  pale  foci  there  may  be  a  greater  or  lesser 
number  of  darkly  pigmented  patches  which  may  have  any 
j  shape.  In  the  case  before  us  we  have  to  deal  with  the  common 
[variety  where  the  foci  in  the  choroid  are  circular  in  outline. 
These  patches  may  coalesce  and  thus  form  oblong  and  irreg- 
ular patches.  With  the  exception  of  a  few  at  the  upper 
border  of  the  figure,  which  already  show  a  dark  border,  all 
the  foci  in  this  case  are  recent,  as  we  see  by  the  haziness  of 
the  outlines  and  the  yellowish-gray  or  yellowish-red  color. 
The  nasal  half  of  the  optic  nerve  is  somewhat  reddened  and 
the  veins  of  the  retina  are  slightly  more  engorged  than  usual. 
Foci  of  this  kind,  as  a  rule,  tend  to  become  converted  into 
white  patches,  owing  to  atrophy  of  the  choroid,  which  allows 
the  sclera  to  shine  through.  Proliferation  of  the  pigment, 
as  a  rule,  is  superadded,  as  we  see  in  the  upper  portion  of  the 
picture  and  especially  in  the  next  figure. 

The  inflammation  is  due  to  accumulations  of  round  cells, 
the  surface  view  of  which  is  shown  in  Figs,  67,  6,  and  70,  and 
a  transverse  view  in  Fig.  79,  a.  The  latter  figure  also  shows, 
in  addition,  the  subsequent  anatomic  changes  that  occur  in 
this  form  of  inflammation. 


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Fig.  70. 


Fig.  70.  Areas  of  Infiltration  (J,  J,  J,)  in  the  Choroid 
in  Disseminated  Choroiditis,  seen  from  above,  so  that  the 
choroidal  vessels  (yellow)  appear  as  in  tlie  ophthalmoscopic 
image,  although  magnified  78  times. — The  stroma  of  the 
choroid  between  the  patches  is  darkly  pigmented  (pigmented 
intervascular  spaces).  While,  under  normal  conditions,  com- 
paratively few  cell-nuclei  are  found  in  the  vessels  in  these 
portions  of  the  tissue,  we  find  thick  accumulations  of  them 
in  this  figure  {J,  J,  Jj)  stained  violet  with  hematoxylin. 
At  the  center  of  the  section  such  an  accumulation  is  seen 
around  the  blood-vessel.  The  inflammatory  area  at  Jj, 
bounded  by  a  straight  line,  is  obscured  on  the  right  by  a 
small  portion  of  retinal  pigment-epithelium  that  adhered  to 
the  preparation,  showing  that  an  area  of  inflammation  in  the 
choroid  may,  under  certain  conditions,  remain  invisible  behind 
the  retinal  pigment-epithelium,  and  become  apparent  only 
after  it  has  reached  a  certain  size  or  has  existed  for  some 
time,  and  has  caused  the  disappearance  of  this  epithelium. 
If,  however,  the  pigmentation  of  the  epithelium  is  slight,  an 
area  of  this  kind  will  be  seen  earlier  in  the  ophthalmoscopic 
image  and  appear  gray  or  yellowish-gray.  It  may  also  happen 
that  the  pigment  of  the  choroid  itself  obscures  small  areas 
of  this  kind,  so  that  they  are  nearly  or  quite  invisible,  as  is 
the  case  in  certain  portions  of  the  present  picture. 

Magnified  78  times. 


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Fig.  72. 


Fig.  72,  a.  Hyaline  Bodies  (Drusen)  in  the  Vitreous  Layer 
of  the  Choroid. — The  patient,  a  womau  sixty-one  years  of 
age,  had  the  same  condition  in  the  eye-ground  of  the  other 
eye,  although  vision  was  normal  on  both  sides.  The  patches 
are  recognized  as  drusen  of  the  vitreous  layer  by  their  position 
behind  the  retinal  vessels,  their  yellowish-white,  somewhat 
shining  color,  and  their  somewhat  circular  outline.  They  are 
usually  found  in  the  neighborhood  of  the  papilla.  The 
anatomic  appearance  of  these  structures  is  shown  in  Fig.  82,  a. 

Fig.  72,  b.  Senile  Pigmentation  of  the  Retina. — The  pict- 
ure was  taken  from  a  man  seventy-six  years  old,  who,  like 
many  persons  of  advanced  age,  showed  pigmentation  at  the 
periphery  of  the  retina  in  both  eyes.  The  pigmented  patches 
appear  in  the  form  of  fine  dots  irregularly  distributed  or  in 
the  form  of  lines  frequently  forming  more  or  less  distinct 
pentagons  and  hexagons.  I  have  seen  these  peculiar  figures 
in  other  similar  cases.  The  visual  field  in  this  man  was 
normal  as  regards  the  external  borders,  though  there  was 
some  contraction  of  the  color-field.  There  was  no  nyctalopia. 
Visual  acuity  was  impaired  by  beginning  cataract.  It  may, 
however,  be  quite  good  in  spite  of  the  retinal  pigmentation, 
as  the  central  portion  of  the  retina  usually  escapes. 

It  is  not  uncommon  to  find  drusen  of  the  vitreous  layer 
in  combination  with  this  form  of  retinal  disease. 

The  pentagonal  and  hexagonal  figures  may  possibly  be  ex- 
plained by  assuming  that  each  figure  contained  within  the 
dark  dotted  lines  corresponds  to  a  vascular  or  lymphatic 
nutritional  region  belonging  to  the  retina  or  choroid,  although 
this  requires  verification  by  more  accurate  anatomic  study. 

This  senile  pigmentation  more  frequently  appears  in  the 
form  of  irregular  figures  and  patches,  as  shown  in  the  upper 
right-hand  portion  of  the  picture. 


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Fig.  74. 


Fig.  74.  Chronic  Disseminated  Choroiditis  and  Secondary 
Pigmentation  of  the  Retina  due  to  the  Presence  in  the  Eye 
of  a  Particle  of  a  Metal  Cap  (direct  method). — While  the 
child  was  pounding  metal  caps  a  small  piece  of  copper  pene- 
trated the  sclera  of  the  right  eye,  close  to  the  inner  corneal 
margin,  and  became  surrounded  by  an  exudate  in  the  form 
of  a  grayish-white  hemispheric  muss  (like  the  one  seen  in 
Fig.  60),  projecting  outward  and  downward  in  front  of  the 
equator  into  the  anterior  portion  of  the  vitreous.  In  the 
neighborhood  of  the  exudate  a  retinal  detachment  occurred 
which  later  disappeared.  Then  the  exudate  surrounding  the 
foreign  body  became  diminished  in  size.  For  a  long  time, 
however,  a  linear  patch  of  exudate  was  seen  passing  through 
the  vitreous  toward  the  optic  nerve.  The  exudate  itself  and 
the  linear  patch  are  seen  in  the  lower  right-hand  portion  of 
the  picture,  which  was  made  a  year  and  a  half  after  the 
injury.  In  the  meantime  a  number  of  patches,  ranging  in 
color  from  yellowish-red  to  black,  appeared  over  the  entire 
visible  portion  of  the  eye-ground,  especially  in  the  inner  lower 
quadrant.  Immediately  after  the  receipt  of  the  injury  a  slight 
optic  neuritis,  and  later  a  macular  disease  in  the  form  of 
minute  dotting  (shown  in  Fig.  53,  b),  made  their  appearance. 
At  the  time  the  picture  was  taken  the  optic  nerve  had  some- 
what regained  its  normal  condition,  but  the  macula  still  showed 
marked  changes,  especially  the  dotting  at  the  periphery.  The 
pigment-patches  resemble  those  seen  in  pigmentary  degenera- 
tion of  the  retina,  and  probably  lie  for  the  most  part  within 
that  membrane. 

During  the  twenty  years  following  the  injury  the  pigmenta- 
tion of  the  retina  increased  considerably,  especially  at  the 
periphery.     Vision  is  still  i. 

This  pigmentary  degeneration  is  also  shown  in  Fig.  46,  o, 
which  was  taken  from  a  similar  case. 


Fig.  75.  Miliary  Tubercles  in  the  Choroid  in  Acute  Mili- 
ary Tuberculosis,  an  appearance  not  rarely  seen  in  this 
disease  shortly  before  death. — The  circular  patches,  some  of 
which  tend  to  coalesce,  are  not  sharply  defined  and,  while 
they  are  small  and  still  partially  covered  by  pigment- 
epithelium,  show  gradations  in  color  from  grayish-white  to 
yellowish-white  and,  finally,  yellowish-red.  The  larger  nod- 
ules occasionally  project  somewhat  and  force  the  retina 
outward,  so  that  they  impart  a  corresponding  bend  to  any 
retinal  vessel  that  may  pass  over  them.  Miliary  tubercles 
are  often  difiicult  to  distinguish  from  the  lesions  of  dissem- 
inated choroiditis,  as,  for  instance,  the  form  shown  in  Fig.  68. 

The  anatomic  features  of  this  disease  of  the  choroid  are 
more  fully  shown  in  the  transverse  sections  of  Fig.  82,  b 
and  c. 


Fig.  76. 


"^^^-^ 


Fig.  76.  Chronic  Tuberculosis  of  the  Choroid  (direct 
method). — The  tuberculous  proliferation,  consisting  of  a  great 
number  of  closely  aggregated  tubercle-nodules — so-called 
conglobate  tubercles — forms  a  slowly  growing  tumor  which, 
even  with  the  ophthalmoscope,  is  seen  to  be  composed  of 
grayish-red  nodules.  The  tumor  lies  at  the  upper  portion 
near  the  periphery ;  its  anterior  border  cannot  be  seen  with 
the  ophthalmoscope,  while  its  posterior  border  is  surrounded 
by  an  irregular  and  ill-defined  pale  border  of  choroid  which 
is  of  some  diagnostic  importance,  as  it  shows  inflammation 
and  corresponding  loosening  of  the  pigment.  In  addition, 
a  number  of  small  disseminated  white  and  yellow  choroiditic 
spots  are  seen  near  the  edge  of  the  border,  giving  one  the 
distinct  impression  that  the  tumor  is  setting  up  inflammation 
in  its  immediate  neighborhood,  a  phenomenon  which  is  con- 
stantly observed  in  tuberculous  proliferations  and  distinguishes 
tEern  from  sarcomaTloFinstance.  We  also  see  that  the  optic 
nerve  is  inflamed,  that  is  to  say,  reddened,  and  not  sharply 
outlined,  although  this  may  be  due  to  the  fact  that  the  boy 
was  suffering  from  a  complication  of  conglobate  tubercles  and 
miliary  tuberculosis  of  the  brain.  (This  case,  in  which  my 
teacher  [Horner]  for  the  first  time  diagnosed  conglobate 
tubercles  of  the  choroid  in  man  with  the  ophthalmoscope, 
I  have  described  more  in  detail,  both  clinically  and  anatom- 
ically, in  Grafe's  Archiv,  vol.  xxv.). 


Fig.  77.  Sarcoma  of  the  Choroid.— The  round,  bluish-gray  tumor  with 
a  somewhat  mottled  surface,  seen  in  the  left  half  of  the  picture,  projected 
into  the  vitreous  from  the  region  of  the  equator  and  obscured  one-half 
of  the  optic  nerve.  In  examining  by  the  direct  method,  if  the  surgeon 
moves  his  head  to  and  fro,  he  will  see  the  edge  of  the  tumor  being  pushed 
over  toward  the  optic  nerve,  showing  that  the  edge  of  the  neoplasm  does 
not  lie  upon  the  optic  nerve,  but  at  some  distance  in  front  of  it,  corre- 
sponding to  the  curve  of  the  roundish  nodule.  The  neoplasm  is  covered 
by  the  retina,  as  we  see  by  the  vessels  which  traverse  it.  The  course 
of  the  vessels  differs  somewhat  from  that  in  the  normal  retina,  being 
slightly  more  tortuous.  The  sarcomatous  nature  of  the  tumor  is  recog- 
nized by  the  dark  color  of  the  entire  mass  and  the  somewhat  fainter 
mottling  of  the  surface.     A  simple  detachment  of  the  retina  would  pre- 

/sent  folds.  At  the  lower  border  of  the  picture  there  is  a  simple  retinal 
detachment  such  as  frequently  accompanies  tumors  of  this  kind.  The 
rest  of  the  eye-ground  is  normal.  In  both  this  and  the  following  case 
we  have  to  deal  with  a  pigmented  sarcoma. 

Fig.  83  shows  the  anatomic  relations  of  this  important  form  of  tumor, 
which  must  be  differentiated  from  chronic  tubercular  proliferation  (see 
remarks  accompanying  Fig.  76)  and  from  glioma  of  the  retina.  The 
latter  tumor  is  rarely  seen  with  the  ophthalmoscope  (see  Fig.  64,  h).  It 
has  no  pigment  and  its  surface  frequently  presents  hemorrhages.  It 
occurs  only  in  youthful  individuals,  while  sarcoma  of  the  choroid,  on 
the  other  hand,  is  rarely  seen  before  the  twelfth  year. 

A  (moderately  pigmented)  choroidal  sarcoma  may  be  simulated  by  an 
invagination  of  the  globe  by  a  tumor  growing  on  the  outside.  This  may 
occur  when  the  tumor  presses  upon  the  side  of  the  eyeball,  and  thus 
gradually  causes  the  wall  to  bulge  in  the  equatorial  region,  without 
penetrating  into  the  interior  of  the  eyeball.  I  have  known  this  to 
happen  in  two  cases  of  carcinoma  in  the  anterior  portion  of  the  orbit, 
originating  from  the  upper  jaw  and  the  cavity  of  the  nose. 

Finally,  sarcoma  must  be  differentiated  from  the  so-called  phantom 
tumors  which  probably  originate  in  the  retina  and  produce  one  or  more 
spherical  prominences  in  the  anterior  portion  of  the  bulb.  They  are 
probably  due  to  cysts  produced  by  senile  degeneration  of  the  retina,  for 
they  not  infrequently  disappear  in  a  short  time  without  leaving  a  trace. 
They  are  usually  seen  by  direct  inspection  or,  after  the  pupil  has  been 
dilated,  by  lateral  illumination. 


Fig.  78.  Sarcoma  of  the  Choroid. — In  this  case  the  pig- 
mented mass  is  considerably  larger  than  in  the  previous  one. 
The  tumor  is  hemispheric  and  the  posterior  border  nearest 
the  optic  nerve  is  not  seen,  because  it  is  obscured  by  the 
overhanging  portion  of  the  neoplasm.  Hence  the  retinal 
vessels  disappear  for  a  time  and  reappear  again  on  the  surface 
of  the  tumor,  where  their  course  is  irregular.  The  pigmenta- 
tion of  this  tumor  is  a  little  less  intense,  and  it  therefore  appears 
paler  than  the  one  in  the  preceding  figure. 


Fig.  79,  a.  Recent  Disseminated  Choroiditis.— The  areas  of  infiltration 
iJJ)  seen  here  in  transverse  section,  instead  of  from  above,  as  in  Figs. 
67  and  70,  lie  between,  and  iu  some  cases  in  front  of,  the  vessels  which 
are  also  seen  in  transverse  section,  and  are  partially  filled  with  blood. 

Fig.  79,  b.  Later  stage  of  the  disease  when  the  retina  is  involved,  that 
is  to  say,  has  already  undergone  connective-tissue  degeneration  wherever 
it  comes  in  contact  with  a  choroidal  focus,  and  thus  becomes  involved  in 
the  disease.  In  places  the  retina  is  reduced  to  a  mere  connective-tissue 
membrane  into  which  the  pigment  from  the  pigment-epithelium  is  begin- 
ning to  penetrate.  The  latter  is  engaged  in  proliferation  ;  some  of  the 
cells  have  lost  their  pigment  and  iu  some  places  the  epithelium  has 
entirely  disappeared.  Underneath,  throughout  the  entire  preparation, 
the  vitreous  layer  of  the  choroid  (L.  r.)  is  seen.  In  the  choroid  we  gee  a 
few  blood-vessels  filled  with  blood,  in  transverse  and  longitudinal  sec- 
tion. On  the  whole,  however,  the  growth  of  connective  tissue  and  scar- 
tissue  is  indicated  by  the  fact  that  the  vessels  and  the  pigment  are  less 
prominent  iu  certain  places.  ,The  round-celled  infiltration  at  J  is  the 
result  of  an  exacerbation  in  the  inflammatory  process.  In  some  places 
the  retina  and  choroid  are  evidently  adherent:  the  open  spaces  between 
these  adhesions,  which  w'ere  in  part  filled  with  exudate  and  pigment, 
have,  for  the  most  part,  lost  their  contents  iu  the  preparation. 

Fig.  79,  c.  In  this  preparation  we  do  not  see  any  recent  inflammatory 
infiltrations.  The  retina  and  choroid  are  thinned,  closely  adherent,  and 
reduced  to  mere  cicatricial  tissue.  In  places  the  pigment-epithelium 
has  uudergone  marked  proliferation  and  projects  into  the  retina  (second- 
ary degeneration  of  the  retina,  cf.  Fig.  43).  In  other  places  the  pigment- 
epithelium  is  altogether  wanting.  In  the  choroid  almost  all  the  vessels 
have  disappeared  and  the  pigment  is  present  only  in  places.  Wherever 
the  pigment  and  the  pigment-epithelium  overlying  it  are  wanting  (as, 
for  instance,  at  the  left  extremity  of  the  figure),  the  sclera  shines 
through  and  thus  forms  the  white  spots  characteristic  of  disseminated 
choroiditis,  while  the  accumulations  of  pigment  (P)  produce  the  black 
spots  seen  in  the  ophthalmoscopic  image. 

The  three  figures  are  magnified  78  times. 


Retina 
J.  J- 


Sklera 


L.v. 


Corp.  vitr. 


Corp.vitr. 


Fig.  79. 


Fig.  80.  Changes  in  the  Choroid  due  to  Violent  Contu- 
sion of  the  Eye ;  Lacerations  of  the  Choroid. — The  eye  was 

severely  contused  by  the  paper  wadding  from  a  blank  cartridge. 
After  the  blood  which  had  been  poured  out  into  the  anterior 
chamber  and  into  the  vitreous  disappeared,  a  large  area  to 
the  nasal  and  lower  side  of  the  optic  nerve  and  half  of  the 
nerve  itself  were  seen  to  be  covered  by  a  whitish  membrane, 
evidently  consisting  of  connective  tissue,  completely  obscuring 
the  retinal  vessels  and  the  borders  of  the  optic  nerve,  as  shown 
in  the  figure.  The  outline  of  this  membrane  consists  of  a 
series  of  bizarre  curves  and  in  places  is  edged  with  black. 
To  the  nasal  side  there  are  five  variously  sized  linear  lacera- 
tions in  the  choroid,  characteristically  arranged  in  concentric 
curves  parallel  with  the  equator,  their  white  color  being  due 
to  the  fact  that  the  sclera  shows  through  the  tears  in  the 
choroid.  They  are  sharply  outlined  and  in  places  slightly 
edged  with  black.  The  retinal  vessels  continue  their  course 
over  the  lacerations  without  interruption.  The  area  between 
the  optic  nerve  and  the  macula  is  finely  dotted.  The  rest  of 
the  eye-ground  is  normal. 


^>fc*^i  ^ 


H^J^^^~~ 


t    C^/'-^  r^t^i^^  /f'- 


FiG.  81.  Sclerosis  of  the  Choroidal  Vessels;  Disseminated 
Choroiditis  and  Secondary  Pigmentation  of  the  Retina.— 

This  figure  is  taken  from  an  unusually  well-developed  case, 
though  we  not  infrequently  see  much  less  pronounced  ex- 
amples in  which  the  alterations  are  confined  to  a  small 
portion  of  the  eye-ground.  The  most  important  features 
of  the  disease  are  the  arteriosclerosis  of  the  choroidal  vessels 
and  the  atrophy  of  the  retinal  pigment,  so  that  the  choroid 
becomes  very  distinct  and  the  choroidal  vessels,  the  walls 
of  which  become  white  and  opaque,  appear  almost  white  on 
a  dark  background,  instead  of  presenting  the  usual  appear- 
ance of  a  red  vascular  plexus.  These  changes  in  the  blood- 
vessels are  most  marked  at  the  anterior  pole  around  the  optic 
nerve  and  gradually  decrease  toward  the  periphery.  On  the 
outskirts  of  the  area  of  greatest  arteriosclerosis  are  a  few 
white  atrophic  patches  in  the  choroid,  some  of  them  with  a 
pigmented  border.  We  also  see  in  this  zone  a  few  angular 
patches,  consisting  only  of  pigment,  which  are  probably  situ- 
ated in  the  retina.  The  retina  is  not  diseased  and  the  walls 
of  its  vessels  show  no  changes. 

The  experiments  of  Wagenmann  have  shown  that  disturb- 
ance of  the  nutrition  of  the  choroid  is  followed  also  by 
atrophy  and  secondary  pigmentation  of  the  retina. 


d.        D. 


Chor. 


Sklera 


f^^. 


^-'^^iiV^- 


Oor. 


Tuherkel 


'•f^^j 


^.^iV 


Chorioidea 


Corp.   vitr.  Retina      ^ 


Sklera, 


V  K.  ^-^ 

Fig.  83. 


Fig.  82.  a.  Hyaline  Bodies  (Drusen)  of  the  Vitreous  Layer 

(cf.  Fig.  72). — The  hyaline  structures,  stained  violet  with 
hematoxylin,  are  seen  upon  the  vitreous  layer  surrounded  for 
the  most  part  by  the  cells  of  the  pigment-epithelium.  The 
choroid  is  normal.  The  retina  in  this  case  was  detached  and 
is,  therefore,  not  seen  in  the  figure. 

Fig.  82,  h.  Miliary  Tubercle  of  the  Choroid  (cf  Fig.  75). 
— As  the  section  is  near  the  equator  and  parallel  to  it, 
most  of  the  choroidal  vessels  appear  in  transverse  section. 
At  the  center  of  the  tubercle  there  are  a  few  giant-cells, 
The  retina  is  not  shown  in  the  drawing.  In  mounting  the 
preparation  the  choroid  became  separated  from  the  sclera 
and  the  interval  is  in  part  filled  with  the  layers  of  the 
suprachoroidea. 

The  patient  died  of  miliary  tuberculosis. 

Fig.  82,  c.  Large  Tubercular  Growth  in  the  Choroid  com- 
posed of  Several  Nodules :  F,  transverse  section  of  a  choroidal 
vessel ;  K,  caseous  portion  of  the  tubercle  ;  R.R.,  giant-cells. 

The  three  figures  appear  magnified  30  times. 


Fig.  83.  Meridional  Sections  through  Eyes  with  Choroidal 
Sarcoma,  stained  with  hematoxylin  and  eosin  (life-size). — 
In  a  there  is  between  the  retina  and  the  tumor  a  layer  of 
amorphous  exudate  similar  to  the  exudate  beneath  the  rest 
of  the  retina  which  is  detached. 

In  h  the  tumor,  except  for  its  posterior  portion,  is  covered 
by  the  retina ;  while  in  c  the  retina  invests  the  entire  surface 
of  the  tumor. 

In  none  of  the  three  cases  did  the  tumor  break  through 
the  sclera. 

In  d  is  shown  the  microscopic  structure  of  a  pigmented 
sarcoma  of  the  choroid,  which  is  seen  to  be  composed  princi- 
pally of  spindle-shaped  cells  containing  more  or  less  pigment, 
though  in  places  the  pigment  is  entirely  absent. 

Magnified  112  times. 


Fig.  83. 


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Fig.  85.  True  Staphyloma  in  a  Highly  Myopic  Eye  (first 
described  by  Weiss). — While  the  pale  atrophic  "sickles"  or 
"  menisci "  at  the  temporal  border  of  the  papilla  or  the  cir- 
cular atrophy  of  the  choroid  around  the  papilla  when  mod- 
erately large,  practically  never,  and  when  quite  large  very 
rarely,  show  any  staphylomatous  bulging,  and  therefore  have 
no  just  claim  to  this  obsolete  designation,  this  is  not  the  case 
in  a  true  staphyloma,  such  as  we  have  represented  here, 
which  is  usually  met  with  only  in  high  grades  of  myopia 
(above  20  D)  and  is  accordingly  uncommon. 

In  this  case  we  see,  especially  to  the  nasal  side  of  the 
papilla,  the  distinct  border  of  an  excavation,  and  the  blood- 
vessels as  they  pass  over  it  are  deflected.  The  edge  of  the 
excavation  is  recognized  either  by  a  more  or  less  marked 
shadow  or  by  a  more  or  less  distinct  gray  line  running  along 
the  summit.  The  curve  varies  considerably  in  size,  that  is 
to  say,  it  may  form  a  greater  or  larger  segment  of  a  circle  or 
of  an  oval.  Occasionally- the  edge  of  the  staphyloma  is  cir- 
cular and  surrounds  the  entire  posterior  pole,  but  even  in 
such  cases  it  is  always  most  pronounced  to  the  nasal  side  of 
the  optic  nerve.  The  edge  of  the  staphyloma  is  best  seen 
by  parallactic  dislocation,  even  when  it  is  difficult  to  see  it 
with  the  ophthalmoscope. 

Fig.  85  shows,  in  addition,  three  atrophic  sickles  near  the 
papilla  over  which  the  vessels  pass  without  undergoing  deflec- 
tion. We  also  note  that  the  course  of  the  retinal  vessels  is 
characteristic  of  a  high  degree  of  myopia :  the  main  trunks, 
instead  of  passing  upward  and  downward,  extend  more  to  the 
temporal  side.  The  posterior  pole  (macula  and  surroundings) 
shows  a  decrease  and  loosening  of  the  pigmentation,  which  is 
also  characteristic  of  a  high  degree  of  myopia.  In  this 
patient  I  removed  the  myopia  of  30  D  by  an  operation  (dis- 
cission of  the  lens),  and  the  eye  became  almost  emmetropic 
with  good  vision. 


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Fig.  87.  Pupillometer. — Since  it  is  quite  easy  in  com- 
paring two  eyes  to  estimate  a  difference  of  a  few  centimeters 
in  the  width  of  the  two  pupils,  it  would  seem  to  be  wise  to 
adopt  a  similar  method  of  measuring  the  pupil  in  daily  prac- 
tice and  to  determine  the  width  of  the  pupil  by  comparing  it 
with  a  painted  picture  of  a  pupil.  A  number  of  black  disks 
arranged  in  a  perpendicular  row  are  held  near  the  eye  and 
the  disk  corresponding  to  the  pupil  is  then  picked  out.  This 
method  is  sufficiently  accurate  for  ordinary  purposes,  as  I  have 
found  in  my  own  practice. 

One  of  the  strips  on  the  opposite  page  should  be  cut  out 
and  attached  to  the  millimeter  measure  which  is  used  for 
measuring  the  pupillary  distance  in  ordering  glasses,  or  it 
may  be  pasted  on  a  strip  of  cardboard.  The  two  other  strips 
will  serve  to  renew  this  simple  instrument. 


Tab.  87. 

•  1.5 

•  2.0 


3.0 
3.5 
4.0 
4.5 
5.0 


6.0 


6.5 


7.0 


•  1.5 

•  2.0 

•  2.5 
0  3.0 
0  3.5 
0  4.0 
A  4.5 


5.0 


6.0 


6.5 


18.0 


7.5 


8.0 


•  1.5 

•  2.0 

•  2.5 
%    3.0 

•  ..5 
#4.0 
#4.5 

A  5.5 
6.0 

6.5 


/.o 


18.0 


NDEX. 


Accommodation  in  direct  method, 

23 
Air-bubble  in  vitreous,  Fig.  56 
Albinismus,  Fig.  10,  b 
Albuminuria,      retina     and     optic 

nerve  in.  Figs.  25,  28,  a 
Albuminuric  disease  of  eve-ground, 

Fig.  28,  h 
Anemia,  pernicious,  eye-ground  in, 
Fig.  31 
retina  in,  Fig.  67,  a 
Anterior  chamber,   angle  of,    after 

glaucoma.  Fig.  24,  6 
Aortic  insufficiency,  arterial  pulsa- 
tion and,  86 
Arteria  centralis  retina^,  80 
Arterial  pulse,  82 

aortic  insufficiency  and,  86 
Arteries,  80 
Astigmatism,  34 
irregular,  37 
measurement,  34 
shadow-test  for,  56 
Atrophic  menisci.  Fig.  85 

sickles.  Fig.  85 
Atrophv  of  choroid  in  mj^opia,  Fig. 
84 
of  optic  nerve.  Figs.  19,  58,  I,  b 
due  to  intra-ocular  tension. 

Fig.  22 
gray.  Fig.  20 
partial.  Fig.  21,  a 
total.  Fig.  21,  6 
of  retinal  vessels.  Fig.  58,  I,  b 


Berlin's  opacity,  Figs.  51,  53 
Blood-vessels,  80 

Brain-tumor,  inflammation  of  optic 
nerve  in.  Fig.  13 


Central    artery,    obstruction    of. 
Fig.  32 
vein,  thrombosis  of,  Fig.  33,  6 


Choked  disc.  Figs.  13,  13,  a,  15 
Chorioretinitis^  Fig.  43 
Choroid  after  contusions,  Fig.  80 
atrophy  of,  in  myopia.  Fig.  84 
chronic  tuberculosis  of,  Fig.  76 
congenital  defects  of,  Figs.  7-10 
diseases  of.  Figs.  68-86 
infiltration    of,    in   disseminated 

choroiditis.  Fig.  70 
lacerations  of.  Fig.  80 
miliary    tubercles   in,    Figs.    75, 

82,  b 
phantom  tumors  of,  Fig.  77 
retina,    and   optic    nerve,    recent 
inflammation  of.  Fig.  73,  a 
and    sclera,    .section    through. 
Fig.  3 
sarcoma  of.  Figs.  77,  78,  83 
tubercular  growth  of.  Fig.  82,  c 
vitreous  layer  of,  hvaliue  bodies 
in.  Figs.  72,  a,  82,  a 
Choroidal  pigmentation,  76 
ring,  76 

vessels,  .sclerosis  of.  Fig.  81 
Choroiditis    dis.seminata.    Figs.    69, 
73,  6 
advanced  case.  Fig.  69 
areas  of  infiltration  in,  Fig.  70 
chronic,   and  pigmentation    of 

retina,  Figs.  43,  74,  81 
early  stage,  Fig.  71 
inflammatory    focus    in.    Fig. 

67,  b 
recent,  Figs.  68,  73,  79 
postica.  Figs.  44,  45 
Cilioretinal  vessel,  81 
Coloboma  choroideae.  Fig.  7 
et  nervi  optici,  Fig.  8,  a 
Color  of  eye-ground,  75 
Colored    illustrations    in    ophthal- 
moscopy, 15 
Commotio  retinae,  Figs.  51,  52 
Congenital  defects.  Figs.  7-11 
Contusion   of   eyeball,    perforation 
after,  Fig.  49 


90 


INDEX. 


Contusions,  choroid  after,  Fig.  80      r 
Corneal  region,  detection  of  opaci-^ 

ties  in,  by  transmitted  light, 

47 
Cylindrical  lens,  36 


Diabetes,  eye-ground  in.  Fig.  30 
Direct    method,    determination    of 
inequalities  by,  45 
enlargement  of  image  in,  43 
mirrors  in,  73 
of  examination,  22 
size  of  field  of  vision  in,  38 
Dislocation  of  lens,  congenital,  Fig. 

11 
Displacement,  parallactic,  46 
Disseminated  choroiditis.  See  Cho- 
roiditis. 
Donders  on  venous  end-pulse,  84 


Ectopia  lentis  congenita.  Fig.  11 
Embolism  of  superior  temporal  ar- 
tery. Fig.  34 
Em  met  rope,  examination  by,  24 
Emmetropic  eve,    direct    examina- 
tion, 24,  27 
examination  in  erect  image,  27 
Endarteritis,    obliterating,    of    su- 
perior temporal  artery,  Fig. 
34  >^ 

Erect  image,  examinations  in,  23 
Erect-image   method   of   examina- 
tion, 22 
Examination  by  indirect  method, 
40 
bj^  transmitted  light,  47 
in  erect  image,  23 
of  eye-ground,  13 
ophthalmoscopic,  67 
first  step,  68 
fourth  step,  72 
second  step,  69 
third  step,  69 
Excavation,  physiologic,  77 
Ej'eball,   contusion  of,   perforation 
of  macula  lutea  after.   Fig. 
49 
Eye-ground,  albuminuric  disease  of, 
Fig.  28,  h 
changes  in,  resulting  from  severe 
forceps  deliverv.  Fig.  58,  I,  a 
color,  75,  76 

colored  illustrations  of,  15 
examination,  13 
illumination,  20 


Eye-ground  in  congenital  syphilis. 
Figs.  41,  42 
in  diabetes.  Fig.  30 
in  hereditary  syphilis.  Fig.  40 
in  leukemia.  Fig.  65 
in  pernicious  anemia.  Fig.  32 
irregularities   on,  determination, 

45 
normal,  73;  Fig.  1 
blonde,  Fig.  4 
dark.  Fig.  5 
observation  of,  22 
point  of  impact  of  foreign  body 

on.  Fig.  58,  a 
rules  for  observing,  32 

Far  point,  26 

Field  of  vision,   size  of,   in  direct 
method,  38 

in  indirect  method,  42 
Flame,    size    of,    ophthalmoscopic 

field  and,  39 
Flux,  intermittent,  83 
Foreign  body  in  vitreous,  Fig.  53 

detection  of,  by  transmitted 
light,  50 
Foveal  reflex,  79 

Glaucoma,  angle  of  anterior  cham- 
ber after.  Fig.  24,  h 
atrophv  of  optic  nerve  from.  Fig, 

22"^ 
optic  nerve  in.  Fig.  24,  c,  d 
Glaucomatous  excavation  of  optic 

nerve.  Fig.  23 
Glioma  of  retina,  Fig.  66 


Haab's  ophthalmoscope,  62 
Heart-disease,  arterial  pulse  and,  86 
Helfreich  on  venous  end-pulse,  84 
Helmholtz's  discs,  21 
Hemorrhages  into  retina.  Fig.  35 

into  vitreous.  Fig.  35 
Homocentric  pencil,  34 
Hyaline   bodies   in   vitreous   laver. 

Figs.  72,  a,  82,_  a 
Hypermetrope,  examination  by,  25 
Hj'permetropia,    detection    of,    by 
transmitted  light,  51 
latent,  30 
manifest,  30 
total,  30 
Hypermetropic  eye,  examination  in 
erect  image,  27 
measurement,  29 


INDEX. 


91 


Illumination  of  eye  under  exam- 
ination, 21 
Image,    enlargement    of,    in    both 

methods,  43 
Indirect    method,    advantages    of, 
over  direct  method,  42 
determination    of    inequaUties 

by,  46 
enlargement  of  image  in,  44 
examination  by,  40 
measurement  of  refraction  by, 

45 
size  of  field  of  vision  in,  42 
Inflammation  of  optic  nerve.   Fig. 
12 
in  brain-tumor.  Fig.  13 
in  orbital  tumor.  Fig.  18 
in  syphilis.  Fig.  16 
intense.  Fig.  17 
Intermittent  flux,  83 
Introduction,  13 
Irregular  astigmatism,  37 

Jackson  on  shadow-test  in  astig- 
matism, 57 
Jackson's  ophthalmoscope,  65 


Keratoconus,    detection    of, 

transmitted  light,  52 
Keratoscopy,  53 


by 


Laceration  in  retinal  detachment, 
Fig.  62 
of  choroid.  Fig.  80 
Latent  hypermetropia,  30 
Lens,  congenital  dislocation  of,  Fig. 
11 
convex,  in  ophthalmoscopes,  62 
in  shadow-test,  choosing  of,  5^ 
cylindrical,  36 

detection    of    opacities    of,     by 
transmitted  light,  48 
Leukemia,  eye-ground  in,  Fig.  65 
Liebreich's  ophthalmoscope,  66 
Loring's  ophthalmoscope,  63 
Randall's  modification,  65 

Macula,  78 

lutea,  disease  of,  from  age.  Fig. 
47 
'  from  blow.  Fig.  48 

from  foreign  body.  Fig.  53 
from  myopia.  Figs.  44,  45 
from  pressure  and  contusion, 
Fig.  54 


Macula  lutea,  horizontal  section  of, 
Fig.  14 
image  in,  34 
in    disease    from    tumor.    Fig. 

50,  a 
perforation  of.  Fig.  49,  a 
strippling  of  eye-ground  in,  79 
reddish-brown  spot  in,  76 
Macular  disease,  Fig.  58,  I,  b 

reflex,  78 
Manifest  hypermetropia,  30 
Marginal  reflex,  80 
Marple's    electric    ophthalmoscope, 

65 
Medullated  fibers  of  retina.  Fig.  6 
Menisci,  atrophic.  Fig.  85 
Miliarv  tubercles  in  choroid,  Figs. 

^75,  82,  6 
Mirror,    concave,    for   shadow-test, 

56 
Mirrors  in  direct  method,  39,  74 
Myope,  examination  by,  24 
Myopia,    atrophy    of,    choroid    in. 
Fig.  84 
detection     of,     bv     transmitted 

light,  51 
disease    of    macula    lutea    from. 
Figs.  44,  45 
Myopic  eye,  measurement  of,  26 
true  staphyloma  in.  Fig.  85 

Nerve-fibers,  medullated,  in  ret- 
ina, Fig.  6 
varicose,    in    retinitis   albuminu- 
rica.  Fig.  26,  6,  c 
Neuritic  atrophy.  Fig.  19 
Neuritis,  optic,  Fig.  12,  a 

and  macular  changes  in  tumor 
of  cerebellum.  Fig.  13,  a 
section  through  papilla  in.  Fig.  15 
Neuroretinitis    albuminurica.    Fig. 
25 
specific.  Fig.  16 
syphilitic.  Fig.  37 
Normal  eye,  section  through  angle 
of  anterior  chamber  of.  Fig. 
24,  a 
eye-ground,    74.     See   also   Eye- 

qround. 
papilla,  longitudinal  section.  Fig. 
2 

Obstruction    of    central    artery, 

Fig-  32 
of  superior  temporal  artery,  tig. 
34 


92 


INDEX. 


Opacities  in  corneal  region,  detec- 
tion of,  by  transmitted  light, 
47 
in  refractive  media,  detection  of, 

by  transmitted  light,  47 
in    vitreous,     detection    of,     by 

transmitted  light,  50 
of  lens,   detection  of,   by  trans- 
mitted light,  48 
Ophthalmoscope,  choice  of,  58 
convex  lens,  62 
description,  18,  58 
Haab's,  62 
Jackson's,  65 
Liebreich's,  66 
Loring's,  63 

Randall's  modification,  64 
Marple's,  65 
Ophthalmoscopic  examination,  67 
first  step,  68 
fourth  step,  72 
second  step,  69 
third  step,  69 
field  of  vision,  size  of,  38 
Optic  disc,  77 
nerve,  77 

and     retina     in     albuminuria. 

Figs.  25,  28,  a 
atrophy  of.     See  Atrophy. 
choroid,  and  retina,  recent  in- 
flammation of.  Fig.  73,  a 
in  orbital  tumor.  Fig.  18 
diseases  of.  Figs.  12-24 
glaucomatous    excavation    of, 

Fig.  23 
in  glaucoma.  Fig.  24,  c,  d 
inflammation  of.     See  Inflam- 
mation. 
left,  viewing  of,  70 
malformation  of,  with  congeni- 
tal choroidal  defect.  Fig.  8,  a 
right,  viewing  of,  71 
through  ophthalmoscope,  76 
neuritis  and  macular  changes  in 
tumor   of    cerebellum,    Fig. 
13,  a 
Opticociliary  vessel,  82 
Orbital   tumor,    inflammation   and 
congestion  of  nerve  in.  Fig. 
18 

Papilla,  77 

normal,  longitudinal  section.  Fig. 

2 
section  through,  in  neuritis,  Fig. 
15 
in  papillitis,  Fig.  15 


Papillitis,  Figs.  13,  15,  17 

section  through  papilla  in.   Fig. 

15 
Parallactic  displacement,  46 
Pencil,  homocentric,  35 
Pernicious  anemia,  eye-ground  in, 

Fig.  31 
retina  in.  Fig.  67,  a 
Phantom  tumors  of  choroid.  Fig.  77 
Phenomena,  pulsation,  82 
Physiologic  excavation,  77 
Pigment,    congenital    absence    of. 

Fig.  10,  h 
Pigmentary  degeneration  of  retina, 

Figs.  38,  39 
Pigmentation,  choroidal,  76 
Pigment-epithelium  of  retina,  con- 
genital defect  of.  Fig.  8,  h 
Posterior  veniB  vorticosse,  Fig.  86 
Pregnancy,     hemorrhagic    retinitis 

of.  Fig.  63 
Pulsation  j^henomena,  82 
Pulse,  arterial,  82,  87 

venous,  84 
Punctum  remotum,  26 
Pupil,  cause  of  black  appearance  of, 

18 
Pupillometer,  Fig.  87 
Pupilloscoi^y,  53 


Randall's    modified   Loring    oph- 
thalmoscope, 65 
Red  coloration  of  normal  eye,  75 
Reflexes  on  retina,  77 
Refracting  power,  measurement  of, 
23 
system  of  eye,  18 
Refraction,  points  to  be  observed, 
33 
Schmidt-Rimpler      method      of 
measuring,  45 
Refractive     media,     detection     of, 
opacities  in,  by  transmitted 
light,  47 
surface  with  greater  curvature  in 
vertical   than  in   horizontal 
meridian,  35 
Retina,  77 

and  optic  nerve  in  albuminuria. 

Figs.  25,  28,  a 
blood-vessels  of,  80 
choroid,  and  optic  nerve,  recent 
inflammation  of.  Fig.  73,  a 
and    sclera,    section    through, 
Fig.  3 
glioma  of,  Fig.  66 


INDEX, 


93 


Retina,  hemorrahges  into,  Fig.  35 
in  pernicious  anemia,  Fig.  67,  a 
in    retinitis    albuminurica,    Figs. 

26,  27,  29 
in  thrombosis  of  vena  centralis 

retinae,  Fig.  50,  6,  c 
inflammation  of,  in  syphilis,  Fig. 

16 
injury  of,  from  iron  splinter.  Figs. 

55,  a,  h,  57 
meduUated  nerve-fibers  in.  Fig.  6 
opacity  of,  from  blow,  Figs.  51, 

52 
pigment  of  congenital  defect  of. 

Fig.  9 
pigmentary  degeneration  of,  Figs. 

38,  39,  46,  c 
pigmentation  of,  choroiditis  and, 
Fig.  81 
disseminated   choroiditis   and. 

Fig.  74 
secondary,  Fig.  46,  a 

in  disseminated  choroiditis. 
Fig.  43 
senile.  Fig.  72,  h 
pigment-epithelium  of,   congeni- 
tal defect  of,  Fig.  8,  6 
pulsation  in,  82 
reflexes  on,  77 

thrombosis   of   blood-vessels   of. 
Fig.  33 
Retinal  arteries,   syphilitic  disease 
of.  Fig.  36 
bands  and  detachment.  Fig.  60 

from  traumatism,  Fig.  58,  h 
detachment.  Figs.  59,  61 
and  bands.  Fig.  60 
funnel-shaped.  Fig.  46,  h 
total.  Fig.  46,  6 
with  laceration.  Fig.  62 
separation,      detection     of,      by 

transmitted  light,  52 
vessels,   atrophy  of.  Fig.  58,  I,  h 
Retinitis  albuminurica.  Figs.  26,  27, 
29 
of  both  eyes.  Fig.  29 
varicose   nerve-fibers   in.    Fig. 
26,  h,  c 
circinata.  Fig.  64 
diabetica.  Fig.  30 
hemorrhagic.  Fig.  33,  a 
of  pregnancy,  hemorrhagic.  Fig. 

63 
pigmentosa.  Figs.  38,  39,  46,  c,  d 
proliferans.  Fig.  58,  6 
Retinoscopy,  48 
Rules  for  observing  eye-ground,  32 


Sarcoma  of  choroid,  Figs.  77,  78,  83 
Schmidt-Rimbler  method  of  meas- 
uring refraction,  45 
Sclera,  retina,  and  choroid,  section 

through.  Fig.  3 
Scleral  ring,  76 
Sclerosis  of  choroidal  vessels,  Fig. 

81 
Senile  macular  disease.  Fig.  47 
Shadow-test,  48 

in  astigmatism,  52 
Sickles,  atrophic,  Fig.  85 
Skiascopy,  53 

in  astigmatism,  56 
Solutio  retiniE,  Fig.  62 
Staphyloma,  true.  Fig.  85 
Strippling  of  eye-ground  in  macula 

lutea,  79 
Superior  temporal  artery,  obstruc- 
tion of.  Fig.  34 
vein,  thrombosis  of,  Fig.  33,  a 
Syphilis,  congenital,  eye-ground  in, 
Figs.  41,  42 
hereditary,   eye-ground   in,    Fig. 

40 
inflammation  of  optic  nerve  in, 
Fig.  16 
of  retina  in.  Fig.  16 
Syphilitic   disease   of  retinal   arte- 
ries. Figs.  36,  37 
neuroretinitis,  Fig.  37 


Temporal    artery,     superior,     ob- 
struction of.  Fig.  34 
vein,     superior,    thrombosis     of, 
Fig.  33,  a 
Thrombosis   of   central    vein.    Fig. 
33,  h 
of  superior  temporal  artery.  Fig. 
34 
veiia.  Fig.  33,  a 
of  vena  centralis  retina?,   retina 
in,  Fig.  50,  6,  c 
Total  hypermetropia,  30 
Transmitted  light,  examination  bv, 

47 
Traumatic  macular  disease.  Fig.  48 
Tubercle,  miliary,  in  choroid.  Figs. 

75,  82,  h 
Tubercular  growth  of  choroid.  Fig. 

82,  c 
Tuberculosis,  acute  miliary,  of  cho- 
roid. Fig.  75 
chronic,  of  choroid,  Fig.  76 
Tumor,  detection  of,  by  transmitted 
light,  52 


94 


INDEX. 


Tumor,    orbital,    macula   lutea  in, 
Fig.  50,  a 
phantom,  of  choroid,  Fig.  77 
Tiirk  on  venous  end-pulse,  86 

Veins,  80 

vortex-,  posterior,  82 
Vena  centralis  retina?,  80 

thrombosis  of,  retina  in.  Fig. 
50,  h,  c 
Venae  vorticosaj,  posterior.  Fig.  86 
Venous  pulse,  82,  83 
Vision,   field   of,   ophthalmoscopic, 
size  of,  38 


Vision,   field  of,   size  of,   in  direct 
method,  38 
in  indirect  method,  42 
Vitreous,  air-bubble  in.  Fig.  56 
connective  tissue  in,  Fig.  58,  I,  6 
foreign  body  in,  Fig.  53 

detection  of,  by  transmitted 
light,  50 
hemorrhages  into,  Fig.  35 
layer,  hvaline  bodies  in.  Figs.  72, 

a,  82,  a 
opacities    in,,  detection    of,    by 
transmitted  light,  50 
Vortex-veins,  posterior,  82 


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